POJ 3468 A Simple Problem with Integers

区间更新区间求和。

题目：http://poj.org/problem?id=3468

#include <stdio.h>
#include <iostream>
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1

using namespace std;
typedef long long ll;
const int maxn = 100005;
ll tree[maxn<<2];
ll flag[maxn<<2];

void PushUp(int rt) {
    tree[rt] = tree[rt<<1] + tree[rt<<1|1];
}
void PushDown(int rt,int m){
    if(flag[rt]){
        flag[rt<<1] += flag[rt];
        flag[rt<<1|1] += flag[rt];
        tree[rt<<1] += (m - (m>>1))*flag[rt];
        tree[rt<<1|1] += (m>>1)*flag[rt];
        flag[rt] = 0;
    }
}
void build(int l,int r,int rt){
    if(l == r){
        scanf("%lld",tree+rt);
        return;
    }
    int m =(l+r)>>1;
    build(lson);
    build(rson);
    PushUp(rt);
}
void update(int L,int R,int p,int l,int r,int rt){
    if(L <= l && r <= R){
        flag[rt] += p;
        tree[rt] += (ll)p*(r-l+1);
        return;
    }
    PushDown(rt, r-l+1);
    int m = (l+r)>>1;
    if(L <= m)
        update(L, R, p, lson);
    if(R > m)
        update(L, R, p, rson);
    PushUp(rt);
}
ll query(int L,int R,int l,int r,int rt){
    if(L <= l && r <= R)
        return tree[rt];
    ll res = 0;
    PushDown(rt, r-l+1);
    int m = (l+r)>>1;
    if(L <= m)
        res += query(L, R, lson);
    if(R > m)
        res += query(L, R, rson);
    return res;
}
int main(){
    int n,q;
    while(~scanf("%d%d",&n,&q)){
        build(1, n, 1);
        while(q--){
            char ch[2];
            int x,y,z;
            scanf("%s",ch);
            if(ch[0] == 'Q'){
                scanf("%d%d",&x,&y);
                printf("%lld\n",query(x, y, 1, n, 1));
            }
            else{
                scanf("%d%d%d",&x,&y,&z);
                update(x, y, z, 1,n,1);
            }
//            for(int i = 1;i < n*4;i++)
//                printf("%lld ",tree[i]);
//            printf("\n");
        }
    }
    return 0;
}