1041 Be Unique

喜欢ヅ旅行 2024-04-08 13:06 53阅读 0赞

## 1041 Be Unique ##

### 0、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: ####

#### Sample Input 2: ####

5 888 666 666 888 888

#### Sample Output 2: ####

None

### 1、大致题意 ###

给n个数字，按照读入顺序，哪个数字是第一个在所有数字中只出现一次的数字。如果所有数字出现都超过了一次，则输出None

### 2、基本思路 ###

简单题。

建立一个数组，存储每个数字出现的次数，然后遍历一遍输入的顺序看是否有出现次数为1的数字

### 3、AC代码 ###

#include <cstdio>
    using namespace std;
    int a[100001], m[100000];
    int main() {
        
        int n;
        scanf("%d", &n);
        for(int i = 0; i < n; i++) {
        
            scanf("%d", &a[i]);
            m[a[i]]++;
        }
        for(int i = 0; i < n; i++) {
        
            if(m[a[i]] == 1) {
        
                printf("%d", a[i]);
                return 0;
            }
        }
        printf("None");
        return 0;
    }

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[17a0a77b7fe84fe48d196ee4d4fd0a5b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/08/aedcc099b8fd40088f05737a93cd38b5.png