PAT 1121. Damn Single (25)
“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.
Each input file contains one test case. For each case, the first line gives a positive integer N (<=50000), 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 (<=10000) 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.
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.
55555 44444 10000 88888 22222 11111 23333
10000 23333 44444 55555 88888
先用一个couple记录一对情侣，比如couple=22222，然后用一个guest数组存储接下来的一行guest，guest[i]表示这个guest的id，如果这个guest[i]的另一半不是-1，那么就设就告诉另一半，你来了，比如guest[i] != -1, 则设 isSCoupleAttent[guest[i]] = 1，比如guest[i] = 11111，那么isCoupleAttent = 1，表示是在guest数组里面的，最后遍历一下guest，看一下guest[i]的另一半是否出席了