题解 | #【模板】线段树1#

板子题

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 5;
int __t = 1, n, q;
int a[N], bit[N];
void update(int idx, int val) {
    while (idx <= n) {
        bit[idx] += val;
        idx += idx & -idx;
    }
}
int query(int idx) {
    int sum = 0;
    while (idx > 0) {
        sum += bit[idx];
        idx -= idx & -idx;
    }
    return sum;
}
void solve() {
    cin >> n >> q;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        update(i, a[i]);
    }
    while (q--) {
        int op, x, y;
        cin >> op >> x >> y;
        if (op == 1) {
            update(x, y);
        } else if (op == 2) {
            cout << query(y) - query(x - 1) << '\n';
        }
    }
}
int32_t main() {
#ifdef ONLINE_JUDGE
    ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    // cin >> __t;
    while (__t--)
        solve();
    return 0;
}