POJ 3468 A Simple Problem with Integers（线段树）

题目地址：http://poj.org/problem?id=3468

思路：updata()区间增减，query()区间求和，会超int用long long

AC代码：

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <cstring>
#include <climits>
#include <cmath>
#include <cctype>

const int inf = 0x3f3f3f3f;//1061109567
typedef long long ll;
const int maxn = 100010;
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
using namespace std;
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] += (m -(m>>1)) * add[rt];
        sum[rt<<1|1] += (m>>1) * add[rt];
        add[rt] = 0;
    }
}
void build(int l,int r,int rt)
{
    add[rt] = 0;
    if(l == r)
    {
        scanf("%I64d",&sum[rt]);
        return;
    }
    int m = (l + r) >> 1;
    build(lson);
    build(rson);
    pushup(rt);
}
void updata(int L,int R,int c,int l,int r,int rt)
{
    if(l >= L && r <= R)
    {
        sum[rt] += (r-l+1) * c;
        add[rt] += c;
        return;
    }
    pushdown(rt,r-l+1);//查询或者更改的时候传递增量
    int m = (l + r) >> 1;
    if(L <= m) updata(L,R,c,lson);
    if(R > m) updata(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);//查询或者更改的时候传递增量
    int m = (l + r) >> 1;
    ll ans = 0;
    if(L <= m) ans += query(L,R,lson);
    if(R > m) ans += query(L,R,rson);
    return ans;
}
int main()
{
    int n,q;
    while(scanf("%d%d",&n,&q) != EOF)
    {
        build(1,n,1);
        char op[2];
        for(int i=0; i<q; i++)
        {
            int a,b,c;
            scanf("%s",op);
            if(op[0] == 'C')
            {
                scanf("%d%d%d",&a,&b,&c);
                updata(a,b,c,1,n,1);
            }
            else
            {
                scanf("%d%d",&a,&b);
                printf("%I64d\n",query(a,b,1,n,1));
            }
        }
    }
    return 0;
}