BestCoder Round #61 (div.2) HDU5522 Numbers

Numbers

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/262144 K (Java/Others)

Total Submission(s): 95 Accepted Submission(s): 72



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

3
3 1 2
3
1 0 2
4
1 1 0 2

Sample Output

YES
NO
YES

Source

BestCoder Round #61 (div.2)

出题人：先排序然后从大到小枚举i，把右边的数用一个数组标记其出现过，

再枚举左边的数判断其加上Ai是否出现过.