Buggy python submission (verdict: Time Limit Exceeded):
import sys
from operator import add, itemgetter


class SegmentTree():
    """
    update, get を提供するSegmentTree

    Attributes
    ----------
    __n : int
        葉の数。2 ^ i - 1
    __dot :
        Segment function
    __e: int
        単位元
    __node: list
        Segment Tree
    """
    def __init__(self, A, dot, e):
        """
        Parameters
        ----------
        A : list
            対象の配列
        dot :
            Segment function
        e : int
            単位元
        """
        n = 2 ** (len(A) - 1).bit_length()
        self.__n = n
        self.__dot = dot
        self.__e = e
        self.__node = [e] * (2 * n)
        for i in range(len(A)):
            self.__node[i + n] = A[i]
        for i in range(n - 1, 0, -1):
            self.__node[i] = self.__dot(self.__node[2 * i], self.__node[2 * i + 1])
    
    def update(self, i, c):
        i += self.__n
        node = self.__node
        node[i] = c
        while i > 1:
            i //= 2
            node[i] = self.__dot(node[2 * i], node[2 * i + 1])

    def get(self, l, r):
        vl, vr = self.__e, self.__e
        l += self.__n
        r += self.__n
        while (l < r):
            if l & 1:
                vl = self.__dot(vl, self.__node[l])
                l += 1
            l //= 2
            if r & 1:
                r -= 1
                vr = self.__dot(vr, self.__node[r])
            r //= 2
        return self.__dot(vl, vr)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    seg = SegmentTree(right, add, 0)

    query = []
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query.append((r - 1, l - 1, i))

    query.sort(reverse=True, key=itemgetter(0))
    ans = [None] * Q

    cur = N - 1
    for r, l, i in query:
        while r < cur:
            c = C[cur] - 1
            p = P[c]
            if len(p):
                seg.update(p.pop(), 1)
            cur -= 1
        tmp = seg.get(l, r + 1)
        ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from operator import add

class SegmentTree():
    """
    update, get を提供するSegmentTree

    Attributes
    ----------
    __n : int
        葉の数。2 ^ i - 1
    __dot :
        Segment function
    __e: int
        単位元
    __node: list
        Segment Tree
    """
    def __init__(self, A, dot, e):
        """
        Parameters
        ----------
        A : list
            対象の配列
        dot :
            Segment function
        e : int
            単位元
        """
        n = 2 ** (len(A) - 1).bit_length()
        self.__n = n
        self.__dot = dot
        self.__e = e
        self.__node = [e] * (2 * n)
        for i in range(len(A)):
            self.__node[i + n] = A[i]
        for i in range(n - 1, 0, -1):
            self.__node[i] = self.__dot(self.__node[2 * i], self.__node[2 * i + 1])
    
    def update(self, i, c):
        i += self.__n
        node = self.__node
        node[i] = c
        while i > 1:
            i //= 2
            node[i] = self.__dot(node[2 * i], node[2 * i + 1])

    def get(self, l, r):
        vl, vr = self.__e, self.__e
        l += self.__n
        r += self.__n
        while (l < r):
            if l & 1:
                vl = self.__dot(vl, self.__node[l])
                l += 1
            l //= 2
            if r & 1:
                r -= 1
                vr = self.__dot(vr, self.__node[r])
            r //= 2
        return self.__dot(vl, vr)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    seg = SegmentTree(right, add, 0)

    query = []
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query.append((r - 1, l - 1, i))

    query.sort(reverse=True)
    ans = [None] * Q

    cur = N - 1
    for r, l, i in query:
        while r < cur:
            c = C[cur] - 1
            # seg.update(cur, 0)
            p = P[c]
            if len(p):
                seg.update(p.pop(), 1)
            cur -= 1
        tmp = seg.get(l, r + 1)
        ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


class BinaryIndexedTree(object):
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = []
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query.append((r - 1, l - 1, i))

    query.sort(reverse=True)
    ans = [None] * Q

    cur = N - 1
    for r, l, i in query:
        while r < cur:
            c = C[cur] - 1
            # BIT.update(cur + 1, 0)
            p = P[c]
            if len(p):
                BIT.add(p.pop() + 1, 1)
            cur -= 1
        tmp = BIT.get(l + 1, r + 1)
        ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


class BinaryIndexedTree(object):
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)
        for i in range(1, self.__n + 1):
            self.add(i, A[i - 1])
            self.__data[i] = A[i - 1]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = []
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query.append((r - 1, l - 1, i))

    query.sort(reverse=True)
    ans = [None] * Q

    cur = N - 1
    for r, l, i in query:
        while r < cur:
            c = C[cur] - 1
            # BIT.update(cur + 1, 0)
            p = P[c]
            if len(p):
                BIT.add(p.pop() + 1, 1)
            cur -= 1
        tmp = BIT.get(l + 1, r + 1)
        ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


class BinaryIndexedTree(object):
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__e = 0
        self.__node = [self.__e] * (self.__n + 1)
        for i in range(1, self.__n + 1):
            self.update(i, A[i - 1])
    
    def update(self, i, v):
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        return self.sum(j) - self.sum(i - 1)


N, Q = map(int, input().split())
C = list(map(int, input().split()))

P = [[] for _ in range(N)]
for i, c in enumerate(C):
    P[c - 1].append(i)

right = [0] * N
for p in P:
    if len(p):
        right[p.pop()] = 1
BIT = BinaryIndexedTree(right)

query = []
for i in range(Q):
    l, r = map(int, sys.stdin.readline().split())
    query.append((r - 1, l - 1, i))

query.sort(reverse=True)
ans = [None] * Q

cur = N - 1
for r, l, i in query:
    while r < cur:
        c = C[cur] - 1
        # BIT.update(cur + 1, 0)
        p = P[c]
        if len(p):
            BIT.update(p.pop() + 1, 1)
        cur -= 1
    tmp = BIT.get(l + 1, r + 1)
    ans[i] = tmp

print(*ans, sep='\n')

Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


class BinaryIndexedTree(object):
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__e = 0
        self.__node = [self.__e] * (self.__n + 1)
        for i in range(1, self.__n + 1):
            self.update(i, A[i - 1])
    
    def update(self, i, v):
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        return self.sum(j) - self.sum(i - 1)


N, Q = map(int, input().split())
C = list(map(int, input().split()))

P = [[] for _ in range(N)]
for i, c in enumerate(C):
    P[c - 1].append(i)

right = [0] * N
for p in P:
    if len(p):
        right[p.pop()] = 1
BIT = BinaryIndexedTree(right)

query = []
for i in range(Q):
    l, r = map(int, sys.stdin.readline().split())
    query.append((r - 1, l - 1, i))

query.sort(reverse=True)
ans = [None] * Q

cur = N - 1
for r, l, i in query:
    while r < cur:
        c = C[cur] - 1
        BIT.update(cur + 1, 0)
        p = P[c]
        if len(p):
            BIT.update(p.pop() + 1, 1)
        cur -= 1
    tmp = BIT.get(l + 1, r + 1)
    ans[i] = tmp

print(*ans, sep='\n')


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


class BinaryIndexedTree(object):
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__e = 0
        self.__node = [self.__e] * (self.__n + 1)
        for i in range(1, self.__n + 1):
            self.update(i, A[i - 1])
    
    def update(self, i, v):
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        return self.sum(j) - self.sum(i - 1)


N, Q = map(int, input().split())
C = list(map(int, input().split()))

P = [[] for _ in range(N)]
for i, c in enumerate(C):
    P[c - 1].append(i)

right = [0] * N
for p in P:
    if len(p):
        right[p.pop()] = 1
BIT = BinaryIndexedTree(right)

query = []
for i in range(Q):
    l, r = map(int, sys.stdin.readline().split())
    query.append((r - 1, l - 1, i))

query.sort(reverse=True)
ans = [None] * Q

cur = N - 1
for r, l, i in query:
    while r < cur:
        c = C[cur] - 1
        BIT.update(cur + 1, 0)
        p = P[c]
        if len(p):
            BIT.update(p.pop() + 1, 1)
        cur -= 1
    tmp = BIT.get(l + 1, r + 1)
    ans[i] = tmp

print(*ans, sep='\n')


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from operator import add

class SegmentTree():
    """
    update, get を提供するSegmentTree

    Attributes
    ----------
    __n : int
        葉の数。2 ^ i - 1
    __dot :
        Segment function
    __e: int
        単位元
    __node: list
        Segment Tree
    """
    def __init__(self, A, dot, e):
        """
        Parameters
        ----------
        A : list
            対象の配列
        dot :
            Segment function
        e : int
            単位元
        """
        n = 2 ** (len(A) - 1).bit_length()
        self.__n = n
        self.__dot = dot
        self.__e = e
        self.__node = [e] * (2 * n)
        for i in range(len(A)):
            self.__node[i + n] = A[i]
        for i in range(n - 1, 0, -1):
            self.__node[i] = self.__dot(self.__node[2 * i], self.__node[2 * i + 1])
    
    def update(self, i, c):
        i += self.__n
        node = self.__node
        node[i] = c
        while i > 1:
            i //= 2
            node[i] = self.__dot(node[2 * i], node[2 * i + 1])

    def get(self, l, r):
        vl, vr = self.__e, self.__e
        l += self.__n
        r += self.__n
        while (l < r):
            if l & 1:
                vl = self.__dot(vl, self.__node[l])
                l += 1
            l //= 2
            if r & 1:
                r -= 1
                vr = self.__dot(vr, self.__node[r])
            r //= 2
        return self.__dot(vl, vr)


N, Q = map(int, input().split())
C = list(map(int, input().split()))

P = [[] for _ in range(N)]
for i, c in enumerate(C):
    P[c - 1].append(i)

right = [0] * N
for p in P:
    if len(p):
        right[p.pop()] = 1
seg = SegmentTree(right, add, 0)

query = []
for i in range(Q):
    l, r = map(int, sys.stdin.readline().split())
    query.append((r - 1, l - 1, i))

query.sort(reverse=True)
ans = [None] * Q

cur = N - 1
for r, l, i in query:
    while r < cur:
        c = C[cur] - 1
        # seg.update(cur, 0)
        p = P[c]
        if len(p):
            seg.update(p.pop(), 1)
        cur -= 1
    tmp = seg.get(l, r + 1)
    ans[i] = tmp

print(*ans, sep='\n')


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from operator import add

class SegmentTree():
    """
    update, get を提供するSegmentTree

    Attributes
    ----------
    __n : int
        葉の数。2 ^ i - 1
    __dot :
        Segment function
    __e: int
        単位元
    __node: list
        Segment Tree
    """
    def __init__(self, A, dot, e):
        """
        Parameters
        ----------
        A : list
            対象の配列
        dot :
            Segment function
        e : int
            単位元
        """
        n = 2 ** (len(A) - 1).bit_length()
        self.__n = n
        self.__dot = dot
        self.__e = e
        self.__node = [e] * (2 * n)
        for i in range(len(A)):
            self.__node[i + n] = A[i]
        for i in range(n - 1, 0, -1):
            self.__node[i] = self.__dot(self.__node[2 * i], self.__node[2 * i + 1])
    
    def update(self, i, c):
        i += self.__n
        node = self.__node
        node[i] = c
        while i > 1:
            i //= 2
            node[i] = self.__dot(node[2 * i], node[2 * i + 1])

    def get(self, l, r):
        vl, vr = self.__e, self.__e
        l += self.__n
        r += self.__n
        while (l < r):
            if l & 1:
                vl = self.__dot(vl, self.__node[l])
                l += 1
            l //= 2
            if r & 1:
                r -= 1
                vr = self.__dot(vr, self.__node[r])
            r //= 2
        return self.__dot(vl, vr)


N, Q = map(int, input().split())
C = list(map(int, input().split()))

P = [[] for _ in range(N)]
for i, c in enumerate(C):
    P[c - 1].append(i)

right = [0] * N
for p in P:
    if len(p):
        right[p.pop()] = 1
seg = SegmentTree(right, add, 0)

query = []
for i in range(Q):
    l, r = map(int, sys.stdin.readline().split())
    query.append((r - 1, l - 1, i))

query.sort(reverse=True)
ans = [None] * Q

cur = N - 1
for r, l, i in query:
    while r < cur:
        c = C[cur] - 1
        seg.update(cur, 0)
        p = P[c]
        if len(p):
            seg.update(p.pop(), 1)
        cur -= 1
    tmp = seg.get(l, r + 1)
    ans[i] = tmp

print(*ans, sep='\n')


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import Counter
from operator import add


class SegmentTree():
    """
    update, get を提供するSegmentTree

    Attributes
    ----------
    __n : int
        葉の数。2 ^ i - 1
    __dot :
        Segment function
    __e: int
        単位元
    __node: list
        Segment Tree
    """
    def __init__(self, A, dot, e):
        """
        Parameters
        ----------
        A : list
            対象の配列
        dot :
            Segment function
        e : int
            単位元
        """
        n = 2 ** (len(A) - 1).bit_length()
        self.__n = n
        self.__dot = dot
        self.__e = e
        self.__node = [e] * (2 * n)
        for i in range(len(A)):
            self.__node[i + n] = Counter({A[i]: 1})
        for i in range(n - 1, 0, -1):
            self.__node[i] = self.__dot(self.__node[2 * i], self.__node[2 * i + 1])
    
    def update(self, i, c):
        i += self.__n
        node = self.__node
        node[i] = c
        while i > 1:
            i //= 2
            node[i] = self.__dot(node[2 * i], node[2 * i + 1])

    def get(self, l, r):
        vl, vr = self.__e, self.__e
        l += self.__n
        r += self.__n
        while (l < r):
            if l & 1:
                vl = self.__dot(vl, self.__node[l])
                l += 1
            l //= 2
            if r & 1:
                r -= 1
                vr = self.__dot(vr, self.__node[r])
            r //= 2
        return self.__dot(vl, vr)


N, Q = map(int, input().split())
C = list(map(int, input().split()))

seg = SegmentTree(C, add, Counter())


for i in range(Q):
    l, r = map(int, sys.stdin.readline().split())
    print(len(seg.get(l - 1, r)))


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import Counter


N, Q = map(int, input().split())
C = list(map(int, input().split()))

e = Counter()
A = [None] * (N + 1)
A[0] = e | e
for i, c in enumerate(C):
    A[i + 1] = A[i] + Counter({c: 1})

for i in range(Q):
    l, r = map(int, sys.stdin.readline().split())
    print(len(A[r] - A[l - 1]))


Fixed submission:
import sys


class BinaryIndexedTree():
    '''
    1-indexed
    '''
    def __init__(self, A):
        self.__n = len(A)
        self.__node = [0] * (self.__n + 1)
        self.__data = [0] * (self.__n + 1)

        S = [0] * (self.__n + 1)
        for i in range(self.__n):
            S[i + 1] = S[i] + A[i]

        for i in range(1, self.__n + 1):
            self.__data[i] = A[i - 1]
            self.__node[i] = S[i] - S[i - (i & -i)]

    def add(self, i, v):
        self.__data[i] += v
        while i <= self.__n:
            self.__node[i] += v
            i += i & -i

    def sum(self, i):
        ''' [1, i]の和
        '''
        rst = 0
        while i > 0:
            rst += self.__node[i]
            i -= i & -i
        return rst
    
    def get(self, i, j):
        '''[i, j]の和
        '''
        if i == j:
            return self.__data[i]
        else:
            return self.sum(j) - self.sum(i - 1)


def main():
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))

    P = [[] for _ in range(N)]
    for i, c in enumerate(C):
        P[c - 1].append(i)

    right = [0] * N
    for p in P:
        if len(p):
            right[p.pop()] = 1
    BIT = BinaryIndexedTree(right)

    query = [[] for _ in range(N)]
    for i in range(Q):
        l, r = map(int, sys.stdin.readline().split())
        query[r - 1].append((l - 1, i))

    ans = [None] * Q

    cur = N - 1
    for r, q in enumerate(reversed(query)):
        r = (N - 1) - r
        while q:
            l, i = q.pop()
            while r < cur:
                c = C[cur] - 1
                # BIT.update(cur + 1, 0)
                p = P[c]
                if len(p):
                    BIT.add(p.pop() + 1, 1)
                cur -= 1
            tmp = BIT.get(l + 1, r + 1)
            ans[i] = tmp

    print(*ans, sep='\n')


if __name__ == '__main__':
    main()