PAT_1041: Be Unique

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 17

Sample Output 1:

31

Sample Input 2:

5 888 666 666 888 888

Sample Output 2:

None

备注：这题太坑了！算法无误（用hash的思想）。刚开始用cin，cout输入输出就超时！改成scanf，printf就A了。我是不是又无知了？

#include<string.h>#include<stdio.h>#define MAXSIZE 100000#define MAXCOUNT 10000int main(){int n,a[MAXSIZE],i;int count[MAXCOUNT];scanf("%d",&n);memset(count,0,MAXCOUNT);for(i=0;i<n;i++){scanf("%d",&a[i]);count[a[i]]++;}for(i=0;i<n;i++){if(count[a[i]]==1){printf("%d",a[i]);return 0;}}printf("None");return 0;}