"Damn Single (单身狗)" is the Chinese nickname for someone who is being single. You are supposed to find those who are alone in a big party, so they can be taken care of.
Input Specification:
Each input file contains one test case. For each case, the first line gives a positive integer N (≤50,000), the total number of couples. Then N lines of the couples follow, each gives a couple of ID's which are 5-digit numbers (i.e. from 00000 to 99999). After the list of couples, there is a positive integer M (≤ 10,000) followed by M ID's of the party guests. The numbers are separated by spaces. It is guaranteed that nobody is having bigamous marriage (重婚) or dangling with more than one companion.
Output Specification:
First print in a line the total number of lonely guests. Then in the next line, print their ID's in increasing order. The numbers must be separated by exactly 1 space, and there must be no extra space at the end of the line.
Sample Input:
3
11111 22222
33333 44444
55555 66666
7
55555 44444 10000 88888 22222 11111 23333
Sample Output:
5
10000 23333 44444 55555 88888//初始化用用-1 //因为有人的编号可能是00000 //所以第二个点不过 #include<cstdio> const int maxn = 100010;int spouse[maxn] = {0};int main(){int n,id1,id2;for(int i = 0; i < maxn; i++) spouse[i] = -1; scanf("%d",&n);while(n--){scanf("%d%d",&id1,&id2);spouse[id1] = id2;spouse[id2] = id1; }scanf("%d",&n);while(n--){scanf("%d",&id1);if(spouse[id1] >= 0 && spouse[spouse[id1]] >= 0){spouse[id1] = -2;}else if(spouse[id1] >= 0 &&spouse[spouse[id1]] == -2){spouse[spouse[id1]] = 2;}else{spouse[id1] = -3;}}int cnt = 0;for(int i = 0; i < maxn; i++){if(spouse[i] < -1) cnt++;}printf("%d\n",cnt);for(int i = 0; i < maxn; i++){if(spouse[i] < -1){printf("%05d",i);cnt--;if(cnt > 0) printf(" ");} }return 0; }
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