POJ3468A Simple Problem with Integers(线段树区间修改)

http://www.notonlysuccess.com/index.php/segment-tree-complete/comment-page-2/#comment-4139

题意:给一组数据,有两个询问,一种是给区间[a,b]上每个数加c,另一种是求区间[a,b]的和!

#include <cstdio>
#include <algorithm>
using namespace std;
 
#define lson l , m , rt << 1
#define rson m + 1 , r , rt << 1 | 1
#define LL long long
const int maxn = 111111;
LL add[maxn<<2];
LL sum[maxn<<2];
void PushUp(int rt) {
    sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}
void PushDown(int rt,int m) {
    if (add[rt]) {
        add[rt<<1] += add[rt];
        add[rt<<1|1] += add[rt];
        sum[rt<<1] += add[rt] * (m - (m >> 1));
        sum[rt<<1|1] += add[rt] * (m >> 1);
        add[rt] = 0;
    }
}
void build(int l,int r,int rt) {
    add[rt] = 0;
    if (l == r) {
        scanf("%lld",&sum[rt]);
        return ;
    }
    int m = (l + r) >> 1;
    build(lson);
    build(rson);
    PushUp(rt);
}
void update(int L,int R,int c,int l,int r,int rt) {
    if (L <= l && r <= R) {
        add[rt] += c;
        sum[rt] += (LL)c * (r - l + 1);
        return ;
    }
    PushDown(rt , r - l + 1);
    int m = (l + r) >> 1;
    if (L <= m) update(L , R , c , lson);
    if (m < R) update(L , R , c , rson);
    PushUp(rt);
}
LL query(int L,int R,int l,int r,int rt) {
    if (L <= l && r <= R) {
        return sum[rt];
    }
    PushDown(rt , r - l + 1);
    int m = (l + r) >> 1;
    LL ret = 0;
    if (L <= m) ret += query(L , R , lson);
    if (m < R) ret += query(L , R , rson);
    return ret;
}
int main() {
    int N , Q;
    scanf("%d%d",&N,&Q);
    build(1 , N , 1);
    while (Q --) {
        char op[2];
        int a , b , c;
        scanf("%s",op);
        if (op[0] == 'Q') {
            scanf("%d%d",&a,&b);
            printf("%lld\n",query(a , b , 1 , N , 1));
        } else {
            scanf("%d%d%d",&a,&b,&c);
            update(a , b , c , 1 , N , 1);
        }
    }
    return 0;
}