Time Limit:1000MS Memory Limit:65536KB 64bit IO Format:%lld & %llu
Description
Farmer John has received a noise complaint from his neighbor, Farmer Bob, stating that his cows are making too much noise.
FJ‘s N cows (1 <= N <= 10,000) all graze at various locations on a long one-dimensional pasture. The cows are very chatty animals. Every pair of cows simultaneously carries on a conversation (so every cow is simultaneously MOOing at all of the N-1 other cows). When cow i MOOs at cow j, the volume of this MOO must be equal to the distance between i and j, in order for j to be able to hear the MOO at all. Please help FJ compute the total volume of sound being generated by all N*(N-1) simultaneous MOOing sessions.
Input
* Line 1: N
* Lines 2..N+1: The location of each cow (in the range 0..1,000,000,000).
Output
There are five cows at locations 1, 5, 3, 2, and 4.
Sample Input
5 1 5 3 2 4
Sample Output
40
Hint
INPUT DETAILS:
There are five cows at locations 1, 5, 3, 2, and 4.
OUTPUT DETAILS:
Cow at 1 contributes 1+2+3+4=10, cow at 5 contributes 4+3+2+1=10, cow at 3 contributes 2+1+1+2=6, cow at 2 contributes 1+1+2+3=7, and cow at 4 contributes 3+2+1+1=7. The total volume is (10+10+6+7+7) = 40.
暴力做的，之前没给牛排序，超时；按位置排序之后就过了
#include<cstdio>
#include<iostream>
#include<cstring>
#include<stdlib.h>
#include<algorithm>
#include<cmath>
using namespace std;
#define N 10005
int c[N];
int main()
{
int n,i,j;
long long ans;
while(scanf("%d",&n)!=EOF)
{
ans=0;
for(i=0;i<n;i++)
{
scanf("%d",&c[i]);
}
sort(c,c+n);
for(i=0;i<n-1;i++)
{
for(j=i+1;j<n;j++)
{
ans+=2*abs(c[i]-c[j]);
}
}
printf("%lld\n",ans);}
return 0;
}