Being unique is so important to people on Mars that even their lottery is designed in a unique way. The rule of winning is simple: one bets on a number chosen from [1, 104]. The first one who bets on a unique number wins. For example, if there are 7 people betting on 5 31 5 88 67 88 17, then the second one who bets on 31 wins.
Input Specification:
Each input file contains one test case. Each case contains a line which begins with a positive integer N (<=105) and then followed by N bets. The numbers are separated by a space.
Output Specification:
For each test case, print the winning number in a line. If there is no winner, print "None" instead.
Sample Input 1:7 5 31 5 88 67 88 17Sample Output 1:
31Sample Input 2:
5 888 666 666 888 888Sample Output 2:
None
题意：找出数列中第一个在数列中只出现一次的数。
思路：很简答的哈希水题，直接哈希就可以了。
#include<iostream>
using namespace std;
int arry[100005],bin[100005];
int main()
{
int n,i,k;
cin>>n;
for(i=0;i<n;i++)
{
cin>>arry[i];
bin[arry[i]]++;
}
int tag=0;
for(i=0;i<n;i++)
{
if(bin[arry[i]]==1)
{
tag=1;
k=arry[i];
break;
}
}
if(tag) cout<<k<<endl;
else cout<<"None"<<endl;
return 0;
}
[哈希]PAT1041 Be Unique,布布扣,bubuko.com
原文：http://blog.csdn.net/zju_ziqin/article/details/19979755