Girls and Boys

Girls and Boys

Time limit:20000/10000 MS (java/others) Memory limit:65536/32768 K (java/others)

Total submission (s): 249 Accepted Submission (s): 163

Problem Description The second year of the University somebody started a study on the romantic relations between the Stude Nts. 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. 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, for n subjects. For each given data set, the program should write to standard output a line containing the result.

Output

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

Sourcesoutheastern Europe 2000

Recommendjgshining

/*first thought: give you a lattice, and then let you ask for the maximum number of connected graphs and find out the idea of a point # error: Test instructions didn't understand test instructions: Find out a maximum set makes any two people have no relationship because it is definitely the relationship between men and women (temporarily do not consider the problem of sexual orientation) so the whole diagram, Connected to the two-point chart, and then using the solution of the binary matching problem with the "Hungarian algorithm" requires the largest non-relational set, that is, the total number of vertices-the maximum number of matches*/#include<bits/stdc++.h>using namespacestd;intn,u,m,v;/*********************** binary matching template **************************/Const intmaxn=1010;intG[MAXN][MAXN];//the number is 0~n-1.intLINKER[MAXN];//Record the matching point of match point I whoBOOLUSED[MAXN];BOOLDfsintU//look back and see if we can make a match by breaking up{    intv;  for(v=0; v<n;v++)        if(g[u][v]&&!Used[v])//If there is this edge, and this side has not been used{Used[v]=true; if(linker[v]==-1|| DFS (Linker[v]))//If the point does not match and you can find a match, you can use this edge as the match point .{Linker[v]=u; return true; }            }      return false; }    intHungary ()//returns the maximum number of matches{    intres=0; intu; MEMSET (linker,-1,sizeof(linker));  for(u=0; u<n;u++) {memset (used,0,sizeof(used)); if(Dfs (U))//If this point has a matching pointres++; }     returnRes; }/*********************** binary matching template **************************/voidinit () {memset (g,0,sizeofg);}intMain () {//freopen ("C:\\users\\acer\\desktop\\in.txt", "R", stdin);     while(SCANF ("%d", &n)! =EOF)        {init ();  for(intI=0; i<n;i++) {scanf ("%d: (%d)",&u,&m);  for(intj=0; j<m;j++) {scanf ("%d",&v); G[U][V]=1; }        }//Building Map        intCur=Hungary (); //cout<<cur<<endl;printf"%d\n", n-cur/2); }    return 0;}

Girls and Boys