HDU 5522 Numbers

Numbers

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/262144 K (Java/Others)
Total Submission(s): 924    Accepted Submission(s): 517

Problem Description

There are n numbers A1,A2....An,your task is to check whether there exists there different positive integers i, j, k (1≤i,j,k≤n) such that Ai−Aj=Ak

 

Input

There are multiple test cases, no more than 1000 cases.
First line of each case contains a single integer n.(3≤n≤100).
Next line contains n integers A1,A2....An.(0≤Ai≤1000)

 

Output

For each case output "YES" in a single line if you find such i, j, k, otherwise output "NO".

 

Sample Input

33 1 231 0 241 1 0 2

 

Sample Output

YESNOYES

 

Source

BestCoder Round #61 (div.2)

 

BestCoder上的一道水题，碰巧看见了。

不多说，没优化，但能过。O(n^3) 暴力

#include <stdio.h>#include <algorithm>using namespace std;const int MAXN=105;int a[MAXN];int main(){        int n;        while(scanf("%d",&n)>0)        {                for(int i=0;i<n;i++)                        scanf("%d",&a[i]);                sort(a,a+n);                int isOk=0;                for(int i=0;i<n;i++)                        for(int j=i+1;j<n;j++)                                for(int k=j+1;k<n;k++)                                        if((a[i]+a[j])==a[k])                                        {                                                isOk=1;                                                break;                                        }                if(isOk)                        printf("YES\n");                else                        printf("NO\n");        }        return 0;}