Buggy python submission (verdict: Time Limit Exceeded):
class SegmentTree:
    def __init__(self, a):
        self.padding = 0
        self.n = len(a)
        self.N = 2 ** (self.n-1).bit_length()
        self.seg_data = [self.padding]*(self.N-1) + a + [self.padding]*(self.N-self.n)
        for i in range(2*self.N-2, 0, -2):
            self.seg_data[(i-1)//2] = self.seg_data[i] + self.seg_data[i-1]
    
    def __len__(self):
        return self.n
    
    def update(self, i, x):
        idx = self.N - 1 + i
        self.seg_data[idx] = x
        while idx:
            idx = (idx-1) // 2
            self.seg_data[idx] = self.seg_data[2*idx+1] + self.seg_data[2*idx+2]
    
    def query(self, i, j):
        # [i, j)
        if i == j:
            return self.seg_data[self.N - 1 + i]
        else:
            idx1 = self.N - 1 + i
            idx2 = self.N - 2 + j # 閉区間にする
            result = self.padding
            while idx1 < idx2 + 1:
                if idx1&1 == 0: # idx1が偶数
                    result = result + self.seg_data[idx1]
                if idx2&1 == 1: # idx2が奇数
                    result = result + self.seg_data[idx2]
                    idx2 -= 1
                idx1 //= 2
                idx2 = (idx2 - 1)//2
            return result
    
    @property
    def data(self):
        return self.seg_data[self.N-1:self.N-1+self.n]


N, Q = map(int, input().split())
C = list(map(int, input().split()))
ans = [0] * Q
last_appeared = [-1] * (N + 1)
st = SegmentTree([0]*N)
li = [[] for i in range(N+1)]
for i in range(Q):
    l, r = map(int, input().split())
    li[r].append((i, l-1))

now = 0
for r in range(1, N+1):
    for i, l in li[r]:
        while now < r:
            c = C[now]
            pre_idx, last_appeared[c] = last_appeared[c], now
            if pre_idx >= 0:
                st.update(pre_idx, 0)
            st.update(now, 1)
            now += 1
        ans[i] = st.query(l, r)


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

Fixed submission:
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
 
 

class SegmentTree:
    def __init__(self, a):
        self.padding = 0
        self.n = len(a)
        self.N = 2 ** (self.n-1).bit_length()
        self.seg_data = [self.padding]*(self.N-1) + a + [self.padding]*(self.N-self.n)
        for i in range(2*self.N-2, 0, -2):
            self.seg_data[(i-1)//2] = self.seg_data[i] + self.seg_data[i-1]
    
    def __len__(self):
        return self.n
    
    def update(self, i, x):
        idx = self.N - 1 + i
        self.seg_data[idx] = x
        while idx:
            idx = (idx-1) // 2
            self.seg_data[idx] = self.seg_data[2*idx+1] + self.seg_data[2*idx+2]
    
    def query(self, i, j):
        # [i, j)
        if i == j:
            return self.seg_data[self.N - 1 + i]
        else:
            idx1 = self.N - 1 + i
            idx2 = self.N - 2 + j # 閉区間にする
            result = self.padding
            while idx1 < idx2 + 1:
                if idx1&1 == 0: # idx1が偶数
                    result = result + self.seg_data[idx1]
                if idx2&1 == 1: # idx2が奇数
                    result = result + self.seg_data[idx2]
                    idx2 -= 1
                idx1 //= 2
                idx2 = (idx2 - 1)//2
            return result
    
    @property
    def data(self):
        return self.seg_data[self.N-1:self.N-1+self.n]


N, Q = map(int, readline().split())
C = list(map(int, readline().split()))
data = list(map(int,read().split()))
lr = [[i, data[2*i], data[2*i+1]] for i in range(0, Q)]
lr.sort(key=lambda x:x[2])

ans = [0] * Q
last_appeared = [-1] * (N + 1)
st = SegmentTree([0]*N)

now = 0
for i, l, r in lr:
    l -= 1
    while now < r:
        c = C[now]
        pre_idx, last_appeared[c] = last_appeared[c], now
        if pre_idx >= 0:
            st.update(pre_idx, 0)
        st.update(now, 1)
        now += 1
    ans[i] = st.query(l, r)


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

Buggy python submission (verdict: Time Limit Exceeded):
class SegmentTree:
    def __init__(self, a):
        self.padding = 0
        self.n = len(a)
        self.N = 2 ** (self.n-1).bit_length()
        self.seg_data = [self.padding]*(self.N-1) + a + [self.padding]*(self.N-self.n)
        for i in range(2*self.N-2, 0, -2):
            self.seg_data[(i-1)//2] = self.seg_data[i] + self.seg_data[i-1]
    
    def __len__(self):
        return self.n
    
    def update(self, i, x):
        idx = self.N - 1 + i
        self.seg_data[idx] = x
        while idx:
            idx = (idx-1) // 2
            self.seg_data[idx] = self.seg_data[2*idx+1] + self.seg_data[2*idx+2]
    
    def query(self, i, j):
        # [i, j)
        if i == j:
            return self.seg_data[self.N - 1 + i]
        else:
            idx1 = self.N - 1 + i
            idx2 = self.N - 2 + j # 閉区間にする
            result = self.padding
            while idx1 < idx2 + 1:
                if idx1&1 == 0: # idx1が偶数
                    result = result + self.seg_data[idx1]
                if idx2&1 == 1: # idx2が奇数
                    result = result + self.seg_data[idx2]
                    idx2 -= 1
                idx1 //= 2
                idx2 = (idx2 - 1)//2
            return result
    
    @property
    def data(self):
        return self.seg_data[self.N-1:self.N-1+self.n]


N, Q = map(int, input().split())
C = list(map(int, input().split()))
ans = [0] * Q
last_appeared = [-1] * (N + 1)
st = SegmentTree([0]*N)

lr = [[i] + list(map(int, input().split())) for i in range(Q)]
lr.sort(key=lambda x:x[2])

now = 0
for i, l, r in lr:
    l -= 1
    while now < r:
        c = C[now]
        pre_idx, last_appeared[c] = last_appeared[c], now
        if pre_idx >= 0:
            st.update(pre_idx, 0)
        st.update(now, 1)
        now += 1
    ans[i] = st.query(l, r)


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

Fixed submission:
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
 
 

class SegmentTree:
    def __init__(self, a):
        self.padding = 0
        self.n = len(a)
        self.N = 2 ** (self.n-1).bit_length()
        self.seg_data = [self.padding]*(self.N-1) + a + [self.padding]*(self.N-self.n)
        for i in range(2*self.N-2, 0, -2):
            self.seg_data[(i-1)//2] = self.seg_data[i] + self.seg_data[i-1]
    
    def __len__(self):
        return self.n
    
    def update(self, i, x):
        idx = self.N - 1 + i
        self.seg_data[idx] = x
        while idx:
            idx = (idx-1) // 2
            self.seg_data[idx] = self.seg_data[2*idx+1] + self.seg_data[2*idx+2]
    
    def query(self, i, j):
        # [i, j)
        if i == j:
            return self.seg_data[self.N - 1 + i]
        else:
            idx1 = self.N - 1 + i
            idx2 = self.N - 2 + j # 閉区間にする
            result = self.padding
            while idx1 < idx2 + 1:
                if idx1&1 == 0: # idx1が偶数
                    result = result + self.seg_data[idx1]
                if idx2&1 == 1: # idx2が奇数
                    result = result + self.seg_data[idx2]
                    idx2 -= 1
                idx1 //= 2
                idx2 = (idx2 - 1)//2
            return result
    
    @property
    def data(self):
        return self.seg_data[self.N-1:self.N-1+self.n]


N, Q = map(int, readline().split())
C = list(map(int, readline().split()))
data = list(map(int,read().split()))
lr = [[i, data[2*i], data[2*i+1]] for i in range(0, Q)]
lr.sort(key=lambda x:x[2])

ans = [0] * Q
last_appeared = [-1] * (N + 1)
st = SegmentTree([0]*N)

now = 0
for i, l, r in lr:
    l -= 1
    while now < r:
        c = C[now]
        pre_idx, last_appeared[c] = last_appeared[c], now
        if pre_idx >= 0:
            st.update(pre_idx, 0)
        st.update(now, 1)
        now += 1
    ans[i] = st.query(l, r)


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

Buggy python submission (verdict: Runtime Error):
class SegmentTree:
    def __init__(self, a):
        self.padding = 0
        self.n = len(a)
        self.N = 2 ** (self.n-1).bit_length()
        self.seg_data = [self.padding]*(self.N-1) + a + [self.padding]*(self.N-self.n)
        for i in range(2*self.N-2, 0, -2):
            self.seg_data[(i-1)//2] = self.seg_data[i] + self.seg_data[i-1]
    
    def __len__(self):
        return self.n
    
    def update(self, i, x):
        idx = self.N - 1 + i
        self.seg_data[idx] = x
        while idx:
            idx = (idx-1) // 2
            self.seg_data[idx] = self.seg_data[2*idx+1] + self.seg_data[2*idx+2]
    
    def query(self, i, j):
        # [i, j)
        if i == j:
            return self.seg_data[self.N - 1 + i]
        else:
            idx1 = self.N - 1 + i
            idx2 = self.N - 2 + j # 閉区間にする
            result = self.padding
            while idx1 < idx2 + 1:
                if idx1&1 == 0: # idx1が偶数
                    result = result + self.seg_data[idx1]
                if idx2&1 == 1: # idx2が奇数
                    result = result + self.seg_data[idx2]
                    idx2 -= 1
                idx1 //= 2
                idx2 = (idx2 - 1)//2
            return result
    
    @property
    def data(self):
        return self.seg_data[self.N-1:self.N-1+self.n]


N, Q = map(int, input().split())
C = list(map(int, input().split()))
ans = [0] * Q
last_appeared = [-1] * N
st = SegmentTree([0]*N)

lr = [[i] + list(map(int, input().split())) for i in range(Q)]
lr.sort(key=lambda x:x[2])

now = 0
for i, l, r in lr:
    l -= 1
    while now < r:
        c = C[now]
        pre_idx, last_appeared[c] = last_appeared[c], now
        if pre_idx >= 0:
            st.update(pre_idx, 0)
        st.update(now, 1)
        now += 1
    ans[i] = st.query(l, r)


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

Fixed submission:
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
 
 

class SegmentTree:
    def __init__(self, a):
        self.padding = 0
        self.n = len(a)
        self.N = 2 ** (self.n-1).bit_length()
        self.seg_data = [self.padding]*(self.N-1) + a + [self.padding]*(self.N-self.n)
        for i in range(2*self.N-2, 0, -2):
            self.seg_data[(i-1)//2] = self.seg_data[i] + self.seg_data[i-1]
    
    def __len__(self):
        return self.n
    
    def update(self, i, x):
        idx = self.N - 1 + i
        self.seg_data[idx] = x
        while idx:
            idx = (idx-1) // 2
            self.seg_data[idx] = self.seg_data[2*idx+1] + self.seg_data[2*idx+2]
    
    def query(self, i, j):
        # [i, j)
        if i == j:
            return self.seg_data[self.N - 1 + i]
        else:
            idx1 = self.N - 1 + i
            idx2 = self.N - 2 + j # 閉区間にする
            result = self.padding
            while idx1 < idx2 + 1:
                if idx1&1 == 0: # idx1が偶数
                    result = result + self.seg_data[idx1]
                if idx2&1 == 1: # idx2が奇数
                    result = result + self.seg_data[idx2]
                    idx2 -= 1
                idx1 //= 2
                idx2 = (idx2 - 1)//2
            return result
    
    @property
    def data(self):
        return self.seg_data[self.N-1:self.N-1+self.n]


N, Q = map(int, readline().split())
C = list(map(int, readline().split()))
data = list(map(int,read().split()))
lr = [[i, data[2*i], data[2*i+1]] for i in range(0, Q)]
lr.sort(key=lambda x:x[2])

ans = [0] * Q
last_appeared = [-1] * (N + 1)
st = SegmentTree([0]*N)

now = 0
for i, l, r in lr:
    l -= 1
    while now < r:
        c = C[now]
        pre_idx, last_appeared[c] = last_appeared[c], now
        if pre_idx >= 0:
            st.update(pre_idx, 0)
        st.update(now, 1)
        now += 1
    ans[i] = st.query(l, r)


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