Problem p02599 (python)

Fixed submission:
# Binary Indexed Tree (Fenwick Tree)
class BIT:
    # 1-index
    def __init__(self, n):
        self.size = n
        self.tree = [0] * (n + 1)
 
    def sum(self, i):
        s = 0
        while i > 0:
            s += self.tree[i]
            i -= i & -i
        return s
 
    def add(self, i, x):
        while i <= self.size:
            self.tree[i] += x
            i += i & -i

N, Q = map(int, input().split())
c = list(map(int, input().split()))
q = []
for k in range(Q):
  l, r = map(int, input().split())
  l -= 1
  r -= 1
  q.append([l, r, k])


q.sort(key = lambda x: x[1])
ans = [0 for k in range(Q)]


good = BIT(N)
lastapp = [-1 for _ in range(N)]
end = -1
for k in range(Q):
  l = q[k][0]
  r = q[k][1]
  a = q[k][2]
  for j in range(r, end, -1):
    if lastapp[c[j]-1] == -1:
      lastapp[c[j]-1] = j
      good.add(j+1, 1)
    elif lastapp[c[j]-1] < j:
      good.add(lastapp[c[j]-1]+1, -1)
      good.add(j+1, 1)
      lastapp[c[j]-1] = j
  ans[a] = good.sum(r+1) - good.sum(l)
  end = r
  
for k in range(Q):
  print(ans[k])

Buggy submission (verdict: Runtime Error):
#https://qiita.com/takayg1/items/c811bd07c21923d7ec69
#####segfunc#####
def segfunc(x, y):
    return x+y
#################

#####ide_ele#####
ide_ele = 0
#################

class SegTree:
    """
    init(init_val, ide_ele): 配列init_valで初期化 O(N)
    update(k, x): k番目の値をxに更新 O(logN)
    query(l, r): 区間[l, r)をsegfuncしたものを返す O(logN)
    """
    def __init__(self, init_val, segfunc, ide_ele):
        """
        init_val: 配列の初期値
        segfunc: 区間にしたい操作
        ide_ele: 単位元
        n: 要素数
        num: n以上の最小の2のべき乗
        tree: セグメント木(1-index)
        """
        n = len(init_val)
        self.segfunc = segfunc
        self.ide_ele = ide_ele
        self.num = 1 << (n - 1).bit_length()
        self.tree = [ide_ele] * 2 * self.num
        # 配列の値を葉にセット
        for i in range(n):
            self.tree[self.num + i] = init_val[i]
        # 構築していく
        for i in range(self.num - 1, 0, -1):
            self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

    def update(self, k, x):
        """
        k番目の値をxに更新
        k: index(0-index)
        x: update value
        """
        k += self.num
        self.tree[k] = x
        while k > 1:
            self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
            k >>= 1

    def query(self, l, r):
        """
        [l, r)のsegfuncしたものを得る
        l: index(0-index)
        r: index(0-index)
        """
        res = self.ide_ele

        l += self.num
        r += self.num
        while l < r:
            if l & 1:
                res = self.segfunc(res, self.tree[l])
                l += 1
            if r & 1:
                res = self.segfunc(res, self.tree[r - 1])
            l >>= 1
            r >>= 1
        return res



N, Q = map(int, input().split())
c = list(map(int, input().split()))
q = []
for k in range(Q):
  l, r = map(int, input().split())
  l -= 1
  r -= 1
  q.append([l, r, k])


q.sort(key = lambda x: x[1])
ans = [0 for k in range(Q)]


good = [0 for _ in range(N)]
good = SegTree(good, segfunc, ide_ele)
lastapp = [-1 for _ in range(N)]
lastapp = SegTree(lastapp, segfunc, ide_ele)
end = -1

for k in range(Q):
  l = q[k][0]
  r = q[k][1]
  a = q[k][2]
  for j in range(r, end, -1):
    if lastapp[c[j]-1] == -1:
      lastapp.update([c[j]-1], j)
      good.update(j, 1)
    elif lastapp[c[j]-1] < j:
      good.update(lastapp[c[j]-1], 0)
      good.update(j, 1)
      lastapp.update([c[j]-1], j)
  ans[a] = good.query(l, r+1)
  end = r
  
for k in range(Q):
  print(ans[k])