// 1041. Be Unique.cpp: 主项目文件。 #include "stdafx.h" #include <cstdio> #include <cstring> const int arrMax=100003; const int N=10003; int arr[arrMax],hash[N],pos[N]; int main() { int n; scanf("%d",&n); memset(hash,0,sizeof(hash)); memset(pos,0,sizeof(pos)); for(int i=0;i<n;i++){ scanf("%d",arr+i); //can't add this unnecessary condition otherwise will time limit //if(hash[arr[i]]==0) pos[arr[i]]=i+1; hash[arr[i]]++; } int needPos=arrMax; for(int i=1;i<=10000;i++){ if(hash[i]==1){ if(pos[i]<needPos) needPos=pos[i]; } } if(needPos==arrMax) printf("None\n"); else printf("%d\n",arr[needPos-1]); return 0; }
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