poj 3468 线段树 成段增减 区间求和

题意：Q是询问区间和，C是在区间内每个节点加上一个值

Sample Input

10 5
1 2 3 4 5 6 7 8 9 10
Q 4 4
Q 1 10
Q 2 4
C 3 6 3
Q 2 4
Sample Output

4
55
9
15

# include <iostream>
# include <cstdio>
# include <cstring>
# include <algorithm>
# include <cmath>
# include <queue>
# define LL long long
using namespace std ;


const int maxn = 100010;

LL sum[maxn<<2] ; //结点开4倍
LL add[maxn<<2] ; //延迟标记

void PushUP(int rt) //更新到父节点
{
    sum[rt] = sum[rt * 2] + sum[rt * 2 + 1] ; //rt 为当前结点
}

void PushDown(int rt , int m )  //向下更新
{
    if (add[rt])
    {
        add[rt * 2] += add[rt] ;
        add[rt * 2 + 1] += add[rt] ;
        sum[rt * 2] += (m - m / 2) * add[rt] ;
        sum[rt * 2 + 1] += (m / 2) * add[rt] ;
        add[rt] = 0 ;
    }
}

void build(int l , int r , int rt) //构建线段树
{
    add[rt] = 0 ;
    if (l == r)
    {
        cin>>sum[rt];
        return ;
    }
    int m = (l + r) / 2 ;
    build(l , m , rt * 2) ;
    build(m + 1 , r , rt * 2 +1) ;
    PushUP(rt) ;
}

void updata(int L , int R , int c , int l , int r , int rt)  //成段增减
{
    if (L <= l && r <= R)
        {
            add[rt] += c ;
            sum[rt] += (r - l + 1) * c ;
            return  ;
        }
    PushDown(rt , r - l + 1) ;
    int m = (l + r) / 2 ;

    if (L <= m)
       updata(L , R , c , l , m , rt * 2) ;
    if (R > m)
       updata(L , R , c , m + 1 , r , rt * 2 + 1) ;
    PushUP(rt) ;
}

LL query(int L , int R , int l , int r , int rt)  //区间求和
{
    if (L <= l && r <= R)
        return sum[rt] ;
    PushDown(rt , r - l + 1) ;
    int m = (l + r) / 2 ;
    LL ret = 0 ;
    if (L <= m)
       ret += query(L , R , l , m , rt * 2) ;
    if (R > m)
       ret += query(L , R , m + 1 , r , rt * 2 + 1) ;
    return ret ;
}

int main ()
{
    //freopen("in.txt","r",stdin) ;
    int n , m ;
    scanf("%d %d" , &n , &m) ;

        build(1 , n , 1) ;
        while(m--)
        {
            char op[10] ;
            int a , b , c ;
            scanf("%s" , op) ;
            if(op[0] == 'Q')
            {
                scanf("%d %d" , &a , &b) ;
                cout<<query(a , b , 1 , n , 1)<<endl ;
            }
            else
            {
              scanf("%d %d %d" , &a , &b , &c) ;
              updata(a , b , c , 1 , n , 1) ;
            }
        }



    return 0 ;
}