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, 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

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分析：把输入存入一个数组中，相应的数值是第一次出现的下标数。如果重复输入，则变为-1，以作区分。

代码：

#include<cstdio>#include<cstdlib>#define Maxn 100001int input[Maxn];int main(void){int N,temp;scanf("%d",&N);int i;for(i=1;i<=N;++i){scanf("%d",&temp);if(input[temp] == 0){input[temp] = i;}else if(input[temp] > 0){input[temp] = -1;}}int min = Maxn;int first = 0;for(i=1;i<Maxn;++i){if(input[i] > 0 && input[i] < min){min = input[i];first = i;}}if(first)printf("%d",first);elseprintf("None");system("pause");return 0;}