1041 Be Unique (20)

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, 10^4^]. 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 (<=10^5^) 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 17

Sample Output 1:

31

Sample Input 2:

5 888 666 666 888 888

Sample Output 2:

None


题目大意：给出一串数字，找出第一个不重复的数字；
思路：用一个数组记录每个数出现的次数, arr[i] = c 表示i出现c次；
　　 用一个数组记录出现的数字，按顺序查找t，当t[i]=1出现当时候，第一个只出现一次的数

#include<iostream>
using namespace std;
int main(){
  int n, temp; 
  cin>>n;
  int arr[10010], *t = new int[n];
  for(int i=0; i<n; i++){
    cin>>temp;
    arr[temp]++;
    t[i] = temp;
  }
  bool flag = true;
  for(int i=0; i<n; i++)
    if(arr[t[i]]==1){ 
      cout<<t[i]<<endl;
      flag = false;
      break;
    }
  if(flag) cout<<"None"<<endl;
  return 0;
}