PAT_A1041 Be Unique (20 分)-优快云博客

本文介绍了一种在火星上流行的独特彩票算法，该算法强调唯一性，通过在[1,10^4]区间内选择唯一投注数字来决定赢家。输入包含一系列投注数字，输出则是第一个唯一的投注数字，如果不存在，则输出'None'。文章提供了C++实现代码，展示了如何使用数组跟踪每个数字的出现次数，从而找出唯一的赢家。

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题目：

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

源码参考：

#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int myarr[10010]={0};

int main()
{
    int N;
    int input_arr[100010];
    scanf("%d",&N);
    for(int i=0;i<N;++i)
    {
        int a;
        scanf("%d",&a);
        input_arr[i]=a;
        myarr[a]++;
    }
    for(int i=0;i<N;++i)
    {
        if(myarr[input_arr[i]]==1)
        {
            printf("%d\n",input_arr[i]);
            return 0;
        }
    }
    printf("None\n"); 
    return 0;
}