题目
http://codevs.cn/problem/1082/
题解
线段树模板没什么好说的,下面贴一个树状数组解法
http://blog.csdn.net/fsahfgsadhsakndas/article/details/52650026
修改区间[l,r]后查询 i( l<= i<= r):
c[l]+=x;
s[l]+=(l-1)*x;
则i点的值会改变 (i-(l-1))*x
代码
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstring>
#define N 200050
#define ll long long
using namespace std;
int n,m,a[N];
ll c[N],c_1[N],c_2[N];//c_1[i]=a[i]-a[i-1]; c_2[i]=(i-1)*c_1[i]
int lowbit(int x)
{
return x&(-x);
}
void update(ll *ar,int p,int x)
{
while(p<=n)
{
ar[p]+=x;
p+=lowbit(p);
}
}
ll sum(ll *ar,int x)
{
ll cnt=0;
while(x)
{
cnt+=ar[x];
x-=lowbit(x);
}
return cnt;
}
int main()
{
scanf("%d",&n);
for(int i=1;i<=n;i++)
{
scanf("%d",&a[i]);
update(c_1,i,a[i]-a[i-1]);
update(c_2,i,(i-1)*(a[i]-a[i-1]));
}
scanf("%d",&m);
while(m--)
{
int opt,a,b;scanf("%d%d%d",&opt,&a,&b);
if(opt==1)
{
int x;scanf("%d",&x);
update(c_1,a,x);update(c_1,b+1,-x);
update(c_2,a,(a-1)*x);update(c_2,b+1,b*(-x));
}
else
{
ll sum1=(a-1)*sum(c_1,a-1)-sum(c_2,a-1);
ll sum2=b*sum(c_1,b)-sum(c_2,b);
printf("%lld\n",sum2-sum1);
}
}
return 0;
}