浙江大学 计算机与软件学院 2019年保研 上机 模拟练习 7-4 Index of Popularity (30 分)

7-4 Index of Popularity (30 分)

The index of popularity (IP) of someone in his/her circle of friends is defined to be the number of friends he/she has in that circle. Now you are supposed to list the members in any given friend circle with top 3 IP’s.

Input Specification:
Each input file contains one test case. Each case starts with a line containing 2 positive integers N and M (both no more than 10​5), which are the total number of people and the number of friend relations, respectively. Hence the people here are numbered from 1 to N.Then M lines follow, each contains the indices of a pair of friends, separated by a space. It is assumed that if A is a friend of B, then B is a friend of A.
Then several queries follow, each occupies a line. For each line of query, K (3≤K≤N), the total number of members in this friend circle is given first, with K indices of members follow. It is guaranteed that all the indices in a circle are distinct.
The input ends when K is zero, and this case must NOT be processed.

Output Specification:
For each query, print in a line the members with top 3 indices of popularity in descending order of their IP’s. If there is a tie, output the one with the smaller number. The numbers must be separated by exactly 1 space, and there must be no extra space at the beginning or the end of the line.

Sample Input:

8 10
2 1
1 3
1 4
1 5
5 8
3 5
2 3
6 3
4 6
3 4
7 8 1 2 3 4 6 5
4 1 3 5 2
4 8 7 4 2
0

分析：给出一个图的各边，及图中若干顶点，找出其中度最大的三个点。
注意点：
1、这道题侧重点不是图的遍历，而是图的存储（当顶点数>100000时，怎么存储？），邻接矩阵是不行，邻接表也有点大，遍历的话会超时，此时可以采用结构体数组来存储边。
2、找出序列中度最大的点，采用map来记录顶点与度。我用了两种方法：1：遍历序列顶点，判断序列中两个点是否有边，有则度++。复杂度n(v*v)太高（运行超时了）2：遍历所有边，判断边的两个点是否在序列中，复杂度n(e)。

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