线段树的单点操作

#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-l)/2;
    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-l)/2;
    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 cas = 1 ; cas <= T ; cas ++)
    {
        printf("Case %d:\n",cas);
        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] == 'S') update(a, -b, 1, n, 1);
            else update(a, b, 1, n, 1);
        }
    }
    return 0;
}