ZOJ 1137二分图匹配最大独立集
2013-10-07 09:19
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Girls and Boys
Time Limit: 10 Seconds
Memory Limit: 32768 KB
the second year of 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 is necessary to find out the maximum set satisfying
the condition: there are no two students in the set who have been ��romantically involved��. The result of the program is the number of students in such a set.
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 an integer number between 0 and n-1, for n subjects.
For each given data set, the program should write to standard output a line containing the result.
An example is given in Figure 1.
Input
7
0: (3) 4 5 6
1: (2) 4 6
2: (0)
3: (0)
4: (2) 0 1
5: (1) 0
6: (2) 0 1
3
0: (2) 1 2
1: (1) 0
2: (1) 0
Output
5
2
Time Limit: 10 Seconds
Memory Limit: 32768 KB
the second year of 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 is necessary to find out the maximum set satisfying
the condition: there are no two students in the set who have been ��romantically involved��. The result of the program is the number of students in such a set.
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 an integer number between 0 and n-1, for n subjects.
For each given data set, the program should write to standard output a line containing the result.
An example is given in Figure 1.
Input
7
0: (3) 4 5 6
1: (2) 4 6
2: (0)
3: (0)
4: (2) 0 1
5: (1) 0
6: (2) 0 1
3
0: (2) 1 2
1: (1) 0
2: (1) 0
Output
5
2
/****************************************************** * 思路:求二分图的最大独立点集 , * 用匈牙利算法先求出最大匹配数 , * 然后用总数减去最大匹配数就是题目要求的答案 * 难度:低 * 解题要点:掌握二分图基本性质即可; * 目测在写一下邻接表版本还有DAG的拆点建图这部分就完了 * 向网络流进军,哈哈 * author:sgx * date:2013/09/06 *******************************************************/ #include <iostream> #include <cstdlib> #include <cstdio> #include <cstring> #include <algorithm> #define A system("pause") using namespace std; const int maxn=1000+5; int map[maxn][maxn],Linker[maxn]; bool used[maxn]; int u,cnt,v; int DFS(int u) { for(int v=0;v<cnt;v++) { if(map[u][v]&&!used[v]) { used[v]=true; if(Linker[v]==-1||DFS(Linker[v])) { Linker[v]=u; return 1; } } } return 0; } int Hungary() { int res=0; memset(Linker,-1,sizeof(Linker)); for(int i=0;i<cnt;i++) { //A; memset(used,0,sizeof(used)); if(DFS(i)) res++; } return res; } int main() { int cnt1; while(scanf("%d",&cnt)!=EOF) { memset(map,0,sizeof(map)); for(int i=0;i<cnt;i++) { scanf("%d: (%d)",&u,&cnt1); while(cnt1--) { scanf("%d",&v); map[u][v]=1; } } //cout<<234<<endl; int res=cnt-Hungary()/2; printf("%d\n",res); } return 0; }
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