1041 Be Unique (20 分)（hash散列）

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

生词

英文	解释
lottery	彩票

题目大意：

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

分析：

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

原文链接：https://blog.csdn.net/liuchuo/article/details/52153050

题解

奇怪的是：v数组用vector存储后两个测试用例会出现段错误。

#include <bits/stdc++.h>

using namespace std;
int v[100010],h[100010];
int main()
{
#ifdef ONLINE_JUDGE
#else
    freopen("1.txt", "r", stdin);
#endif
    int n;
    //vector<int> v(n);
    scanf("%d",&n);
    for(int i=0;i<n;i++)
    {
        scanf("%d",&v[i]);
        h[v[i]]++;
    }
    for(int i=0;i<n;i++){
        if(h[v[i]]==1){
            printf("%d\n",v[i]);
            return 0;
        }
    }
    printf("None\n");
    return 0;
}