HDU1166 线段树——单点更新

#include<cstdio>
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
const int maxn = 55555;
int sum[maxn << 2];
void pushup(int rt)
{
    sum[rt] = sum[rt << 1] + sum[rt << 1 | 1];
}
void build(int l, int r, int rt)
{
    if (l == r){
        scanf("%d", &sum[rt]);
        return;
    }
    int m = (l + r) >> 1;
    build(lson);
    build(rson);
    pushup(rt);
}
void update(int p, int add, int l, int r, int rt)
{
    if (l == r){
        sum[rt] += add;
        return;
    }
    int m = (l + r) >> 1;
    if (p <= m)update(p,add,lson);
    else update(p,add,rson);
    pushup(rt);
}
int query(int L, int R, int l, int r, int rt)
{
    if (L <= l&&r <= R)
    {
        return sum[rt];
    }
    int m = (l + r) >> 1;
    int ret = 0;
    if (L <= m) ret += query(L, R, lson);
    if (R > m) ret += query(L, R, rson);
    return ret;
}
int main()
{
    int T, n;
    scanf("%d", &T);
    for (int i = 1; i <= T; i++){
        printf("Case %d:\n", i);
        scanf("%d", &n);
        build(1, n, 1);
        char op[10];
        while (scanf("%s", op)){
            if (op[0] == ‘E‘) break;
            int a, b;
            scanf("%d%d", &a, &b);
            if (op[0] == ‘Q‘) printf("%d\n",query(a, b, 1, n, 1));
            else if (op[0] == ‘A‘) update(a, b, 1, n, 1);
            else update(a, -b, 1, n, 1);
        }
    }
    return 0;
}