PAT 1041. Be Unique (20)

//1041#include<stdio.h>int main(){int n;int i;int a;int num[100008];int flag[10008];int j;int k = 0;int tag = 0;scanf("%d",&n);for(i=0;i<=1000;i++){flag[i] = 0;}for(i=0;i<n;i++){scanf("%d",&num[i]);flag[num[i]]++;}for(i=0;i<n;i++){if(flag[num[i]]==1){printf("%d",num[i]);break;}}if(i==n)printf("None");return 0;}