pat1041 Be Unique

#include<cstdio>#include<iostream>#include<algorithm>#include<vector>#include<queue>#include<string>#include<cstring>#include<cmath>#include<map>#define ll long longusing namespace std;int h[10004],a[100005];int main(){  int n,i,j,f;  while(scanf("%d",&n)!=EOF)  {  memset(h,0,sizeof(h));  for(i = 1;i<=n;i++)  {  scanf("%d",&a[i]);  h[a[i]]++;  }  f = 0;  for(i = 1;i<=n;i++)  {  if(h[a[i]] == 1)  {  printf("%d\n",a[i]);  f = 1;  break;  }  }  if(!f)printf("None\n");  }  return 0;}