BOJ - 2042 - 구간 합 구하기

import sys, math

def init(arr, tree, node, start, end):
    if start == end:
        tree[node] = arr[start]
        return tree[node]

    mid = (start + end) // 2
    tree[node] = init(arr, tree, node * 2, start, mid) + \
                 init(arr, tree, node * 2 + 1, mid + 1, end)
    return tree[node]

def updateValue(tree, node, left, right, target, value):
    if (target < left or right < target): return 0
    tree[node] += value
    if left == right: return 0

    mid = (left + right) // 2
    updateValue(tree, node * 2, left, mid, target, value)
    updateValue(tree, node * 2 + 1, mid + 1, right, target, value)

def sumValue(tree, node, start, end, left, right):

    if (right < start or end < left): return 0
    elif (left <= start and end <= right): return tree[node]

    mid = (start + end) // 2
    return sumValue(tree, node * 2, start, mid, left, right) + \
           sumValue(tree, node * 2 + 1, mid + 1, end, left, right)

def solution():
    N, M, K = map(int, sys.stdin.readline().split())

    arr = []
    for i in range(N):
        arr.append(int(sys.stdin.readline()))

    height = int(math.ceil(math.log2(N)))
    treeSize = 1 << (height + 1)
    segmentTree = [0] * treeSize

    init(arr, segmentTree, 1, 0, N-1)

    for i in range(M + K):
        command = list(map(int, sys.stdin.readline().split()))

        if command[0] == 1:
            value = command[2] - arr[command[1] - 1]
            arr[command[1] - 1] = command[2]
            updateValue(segmentTree, 1, 0, N-1, command[1] - 1, value)

        else:
            print(sumValue(segmentTree, 1, 0, N-1, command[1]-1, command[2]-1))

solution()

https://www.acmicpc.net/problem/2042