题解 | #【模板】线段树1#

#include <stdio.h>

#define ll long long
#define N 100100
ll a[N], tree[N];

int lowbit(int x) {
    return x & -x;
}
void add(int now, ll val) {
    for(int i = now; i < N; i += lowbit(i)) {
        tree[i] += val;
    }
}
ll query(int now) {
    ll res = 0;
    for(int i = now; i > 0; i -= lowbit(i)) {
        res += tree[i];
    }
    return res;
}
int main() {
    int n, q;
    if(scanf("%d %d", &n, &q) != EOF) {
        for(int i = 1; i <= n; i++) {
            if(scanf("%lld", &a[i]) == EOF) {
                printf("error2\n");
                return 1;
            }
        }
        for(int i = 1; i <= n; i++) {
            add(i, a[i]);
        }
        while(q--) {
            int p, x, y;
            if(scanf("%d %d %d", &p, &x, &y) != EOF) {
                if(p == 1) {
                    add(x, -a[x]);
                    a[x] += y;
                    add(x, a[x]);
                } else if(p == 2) {
                    printf("%lld\n", query(y) - query(x - 1));
                } else printf("error4\n");
            } else printf("error3\n");
        }
    } else printf("error1\n");
    return 0;
}