Buggy python submission (verdict: Time Limit Exceeded):
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = stdin.buffer.readline

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()


Fixed submission:
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = stdin.buffer.readline

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()

Buggy python submission (verdict: Time Limit Exceeded):
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = lambda: stdin.readline().strip()

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()


Fixed submission:
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = stdin.buffer.readline

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()

Buggy python submission (verdict: Time Limit Exceeded):
# Reference: https://qiita.com/dn6049949/items/afa12d5d079f518de368

# self.data: 1-indexed
#    __1__
#  _2_   _3_
# 4   5 6   7

# f(f(a, b), c) == f(a, f(b, c))

class SegmentTree:
    # a = [default] * n
    # O(n)
    def __init__(self, n, default=-2**30):
        self.num_leaf = 2 ** (n-1).bit_length()
        self.data = [default] * (2*self.num_leaf)

    # a[i] = x
    # O(log(n))
    def update(self, i, x):
        i += self.num_leaf
        self.data[i] = x
        i >>= 1
        while i > 0:
            self.data[i] = self.data[2*i] + self.data[2*i+1]
            i >>= 1

    # return f(a[l:r])
    # O(log(n))
    def query(self, l, r):
        l += self.num_leaf
        r += self.num_leaf - 1
        lres, rres = self.data[0], self.data[0] # self.data[0] == default
        while l < r:
            if l & 1:
                lres = lres + self.data[l]
                l += 1
            if not r & 1:
                rres = self.data[r] + rres
                r -= 1
            l >>= 1
            r >>= 1
        if l == r:
            res = lres + self.data[l] + rres
        else:
            res = lres + rres
        return res

from sys import stdin
input = lambda: stdin.readline().strip()

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    st = SegmentTree(n, default=0)
    for i in range(n+1):
        if len(lis[i]) > 0:
            st.update(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            st.update(now_r, 0) # delete
            if len(lis[c[now_r]]) > 0:
                st.update(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = st.query(l, r)
    
    for i in ans:
        print(i)

main()


Fixed submission:
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = stdin.buffer.readline

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()

Buggy python submission (verdict: Time Limit Exceeded):
# Reference: https://qiita.com/dn6049949/items/afa12d5d079f518de368

# self.data: 1-indexed
#    __1__
#  _2_   _3_
# 4   5 6   7

# f(f(a, b), c) == f(a, f(b, c))

class SegmentTree:
    # a = [default] * n
    # O(n)
    def __init__(self, n, f=max, default=-2**30):
        self.num_leaf = 2 ** (n-1).bit_length()
        self.data = [default] * (2*self.num_leaf)
        self.f = f

    # a[i] = x
    # O(log(n))
    def update(self, i, x):
        i += self.num_leaf
        self.data[i] = x
        i >>= 1
        while i > 0:
            self.data[i] = self.f(self.data[2*i], self.data[2*i+1])
            i >>= 1

    # return f(a[l:r])
    # O(log(n))
    def query(self, l, r):
        l += self.num_leaf
        r += self.num_leaf - 1
        lres, rres = self.data[0], self.data[0] # self.data[0] == default
        while l < r:
            if l & 1:
                lres = self.f(lres, self.data[l])
                l += 1
            if not r & 1:
                rres = self.f(self.data[r], rres)
                r -= 1
            l >>= 1
            r >>= 1
        if l == r:
            res = self.f(self.f(lres, self.data[l]), rres)
        else:
            res = self.f(lres, rres)
        return res

from sys import stdin
input = lambda: stdin.readline().strip()

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    st = SegmentTree(n, f=lambda x, y: x + y, default=0)
    for i in range(n+1):
        if len(lis[i]) > 0:
            st.update(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])
    
    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            st.update(now_r, 0) # delete
            if len(lis[c[now_r]]) > 0:
                st.update(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = st.query(l, r)
    
    for i in ans:
        print(i)

main()

Fixed submission:
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = stdin.buffer.readline

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()

Buggy python submission (verdict: Time Limit Exceeded):
# Reference: https://qiita.com/dn6049949/items/afa12d5d079f518de368

# self.data: 1-indexed
#    __1__
#  _2_   _3_
# 4   5 6   7

# f(f(a, b), c) == f(a, f(b, c))

class SegmentTree:
    # a = [default] * n
    # O(n)
    def __init__(self, n, f=max, default=-2**30):
        self.num_leaf = 2 ** (n-1).bit_length()
        self.data = [default] * (2*self.num_leaf)
        self.f = f

    # a[i] = x
    # O(log(n))
    def update(self, i, x):
        i += self.num_leaf
        self.data[i] = x
        i >>= 1
        while i > 0:
            self.data[i] = self.f(self.data[2*i], self.data[2*i+1])
            i >>= 1

    # return f(a[l:r])
    # O(log(n))
    def query(self, l, r):
        l += self.num_leaf
        r += self.num_leaf - 1
        lres, rres = self.data[0], self.data[0] # self.data[0] == default
        while l < r:
            if l & 1:
                lres = self.f(lres, self.data[l])
                l += 1
            if not r & 1:
                rres = self.f(self.data[r], rres)
                r -= 1
            l >>= 1
            r >>= 1
        if l == r:
            res = self.f(self.f(lres, self.data[l]), rres)
        else:
            res = self.f(lres, rres)
        return res

from sys import stdin
input = lambda: stdin.readline().strip()

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))
    
    st = SegmentTree(n, f=lambda x, y: x | y, default=set([]))
    for i, ci in enumerate(c):
        st.update(i, {ci})
    
    ans = [0] * q
    for lap in range(q):
        l, r = map(int, input().split())
        ans[lap] = len(st.query(l-1, r))
    
    for i in ans:
        print(i)

main()

Fixed submission:
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = stdin.buffer.readline

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()

Buggy python submission (verdict: Time Limit Exceeded):
def main():
    from sys import stdin
    def input():
        return stdin.readline().strip()
    
    _, q = map(int, input().split())
    c = list(map(int, input().split()))

    ans = []
    for _ in range(q):
        l, r = map(int, input().split())
        ans.append(len(set(c[l-1:r])))

    for i in ans:
        print(i)

main()

Fixed submission:
# Reference: https://ikatakos.com/pot/programming_algorithm/data_structure/binary_indexed_tree
class BinaryIndexedTree:
    # a = [0] * n
    def __init__(self, n):
        self.size = n
        self.data = [0] * (n+1)

    # return sum(a[0:i])
    def cumulative_sum(self, i):
        ans = 0
        while i > 0:
            ans += self.data[i]
            i -= i & -i
        return ans

    # a[i] += x
    def add(self, i, x):
        i += 1
        while i <= self.size:
            self.data[i] += x
            i += i & -i

from sys import stdin
input = stdin.buffer.readline

def main():
    n, q = map(int, input().split())
    c = list(map(int, input().split()))

    lis = [[] for _ in range(n + 1)]
    for i, ci in enumerate(c):
        lis[ci].append(i)

    BIT = BinaryIndexedTree(n)
    for i in range(n+1):
        if len(lis[i]) > 0:
            BIT.add(lis[i].pop(-1), 1)

    query = [0] * q
    ans = [-1] * q
    for lap in range(q):
        l, r = map(int, input().split())
        query[lap] = (l-1, r, lap)
    
    query.sort(reverse=True, key=lambda x: x[1])

    now_r = n
    for ind, (l, r, lap) in enumerate(query):
        while now_r > r:
            now_r -= 1
            BIT.add(now_r, -1) # delete
            if len(lis[c[now_r]]) > 0:
                BIT.add(lis[c[now_r]].pop(-1), 1) # add
        ans[lap] = BIT.cumulative_sum(r) - BIT.cumulative_sum(l)
    
    for i in ans:
        print(i)

main()