线段树

单点修改 区间查询 模板(维护区间和)

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int N = 5e5 + 10;
int t[N * 4], a[N], n;
void build(int cur, int l, int r)
{
    if (l == r)
    {
        t[cur] = a[l];
    }
    else
    {
        int mid = (l + r) >> 1;
        build(cur * 2, l, mid);
        build(cur * 2 + 1, mid+1, r);
        //合并
        t[cur] = t[cur * 2] + t[cur * 2 + 1];
    }
}
void modify(int cur, int l, int r, int x, int y)\
{
    //x位置加上y
    if (l == r)
    {
        t[cur] += y;
    }
    else
    {
        int mid = (l + r) >> 1;
        if (x > mid)
        {
            modify(cur * 2 + 1, mid + 1, r, x, y);
        }
        else
        {
            modify(cur * 2, l, mid, x, y);
        }
        //合并
        t[cur] = t[cur * 2] + t[cur * 2 + 1];
    }
}
int find(int cur, int l, int r, int x, int y)
{
    //查询x->y的信息
    if (l == x && r == y)
    {
        return t[cur];
    }
    int mid = (l + r) >> 1;
    if (y <= mid)
    {
        //全在左
        return find(cur * 2, l, mid, x, y);
    }
    else if (x > mid)
    {
        //全在右
        return find(cur * 2 + 1, mid + 1, r, x, y);
    }
    else
    {
        //两边都有
        int p1 = find(cur * 2, l, mid, x, mid);
        int p2 = find(cur * 2 + 1, mid + 1, r, mid + 1, y);
        return p1 + p2;
    }
}
//线段树
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    build(1, 1, n);
    while (m--)
    {
        int op, x, y;
        cin >> op >> x >> y;
        if (op == 1)
        {
            modify(1, 1, n, x, y);
        }
        else
        {
            cout << find(1, 1, n, x, y) << '\n';
        }
    }
    return 0;
}