Hdu1068/poj1466_girls and Boys (binary Graph/Max Independent set =n-Max match)

Problem Solving Report

http://blog.csdn.net/juncoder/article/details/38160591

Topic Portal (POJ)

Topic Portal (HDU)

Test instructions

Maximum set of conditions to satisfy: No matter what two people in the collection have no romantic relationship

Ideas:

The same problem as POJ2771, the change is much simpler. POJ2771 Problem Solving Report

#include <cstdio> #include <cstring> #include <iostream> #include <algorithm>using namespace Std;int n,mmap[550][550],pre[550],vis[550];int dfs (int x) {for    (int i=0; i<n; i++) {        if (!vis[i]&& Mmap[x][i]) {            vis[i]=1;            if (pre[i]==-1| | DFS (Pre[i])) {                pre[i]=x;                return 1;}}    }    return 0;} int main () {    int i,j,a,b,k;    while (~SCANF ("%d", &n)) {        memset (mmap,0,sizeof (mmap));        memset (pre,-1,sizeof (pre));        for (I=1; i<=n; i++) {            scanf ("%d: (%d)", &a,&k);            for (j=1; j<=k; J + +) {                scanf ("%d", &b);                mmap[a][b]=1;            }        }        int ans=0;        for (i=0; i<n; i++) {            memset (vis,0,sizeof (Vis));            Ans+=dfs (i);        }        printf ("%d\n", N-ANS/2);    }    return 0;}

Girls and Boys

Time Limit: 5000MS		Memory Limit: 10000K
Total Submissions: 10348		Accepted: 4608

Description

In the second, the university somebody started a study on the romantic relations between the students. The relation "romantically involved" is defined between one girl and one boy. For the study reasons it was necessary to find out the the maximum set satisfying the condition:there was no and the students in T He set who has been "romantically involved". The result of the program was the number of students in such a set.

Input

The input contains several data sets in text format. Each data set represents one set of subjects of the study, with the following description:

The number of students
The description of each student, in the following format
Student_identifier: (number_of_romantic_relations) student_identifier1 student_identifier2 student_identifier3 ...
Or
Student_identifier: (0)

The Student_identifier is a integer number between 0 and n-1 (n <=500), for n subjects.

Output

For each given data set, the program should write to standard output a line containing the result.

Sample Input

70: (3) 4 5 61: (2) 4 62: (0) 3: (0) 4: (2) 0 15: (1) 06: (2) 0 130: (2) 1 21: (1) 02: (1) 0

Sample Output

52

Hdu1068/poj1466_girls and Boys (binary Graph/Max Independent set =n-Max match)