下面是代码

#include <stdio.h>

int lowbit(int x) {
    return x & (-x);
}

int tree[1000001];
int n, m;

void Add(int pos, int x) {
    for(int i = pos; i <= n; i += lowbit(i))
        tree[i] += x;
}

int Ask(int pos) {
    int ans = 0;
    for(int i = pos; i; i -= lowbit(i))
        ans += tree[i];
    return ans;
}

int main() {
    scanf("%d %d", &n, &m);
    int last, now;
    for(int i = 1; i <= n; ++i) {
        scanf("%d", &now);
        Add(i, now - last);
        last = now;
    }
    for(int i = 1; i <= m; ++i) {
        int opt, x, y, k;
        scanf("%d %d", &opt, &x);
        if(opt == 1) {
            scanf("%d %d", &y, &k);
            Add(x, k), Add(y + 1, -k);
        }
        else
            printf("%d\n", Ask(x));
    }
    return 0;
}

编译器版本是这个

gcc version 13.2.0 (x86_64-win32-seh-rev1, Built by MinGW-Builds project)