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HDU 1669 二分圖多重匹配+二分

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Jamie‘s Contact Groups

Time Limit: 15000/7000 MS (Java/Others) Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 747 Accepted Submission(s): 303


Problem Description Jamie is a very popular girl and has quite a lot of friends, so she always keeps a very long contact list in her cell phone. The contact list has become so long that it often takes a long time for her to browse through the whole list to find a friend‘s number. As Jamie‘s best friend and a programming genius, you suggest that she group the contact list and minimize the size of the largest group, so that it will be easier for her to search for a friend‘s number among the groups. Jamie takes your advice and gives you her entire contact list containing her friends‘ names, the number of groups she wishes to have and what groups every friend could belong to. Your task is to write a program that takes the list and organizes it into groups such that each friend appears in only one of those groups and the size of the largest group is minimized.

Input There will be at most 20 test cases. Ease case starts with a line containing two integers N and M. where N is the length of the contact list and M is the number of groups. N lines then follow. Each line contains a friend‘s name and the groups the friend could belong to. You can assume N is no more than 1000 and M is no more than 500. The names will contain alphabet letters only and will be no longer than 15 characters. No two friends have the same name. The group label is an integer between 0 and M - 1. After the last test case, there is a single line `0 0‘ that terminates the input.

Output For each test case, output a line containing a single integer, the size of the largest contact group.

Sample Input 3 2 John 0 1 Rose 1 Mary 1 5 4 ACM 1 2 3 ICPC 0 1 Asian 0 2 3 Regional 1 2 ShangHai 0 2 0 0 Sample Output 2 2 解析:有n個人,m個分組,每個人都可以分到指定的幾個組合,問怎麽分組使得m個組中的最大組的大小最小。 顯然是一對多的關系,然後我們二分 二分圖多重匹配 的限制,找到可以使n個人都可以匹配的最小限制就好了。 AC代碼
#include <bits/stdc++.h>
#define
pb push_back #define mp make_pair #define fi first #define se second #define all(a) (a).begin(), (a).end() #define fillchar(a, x) memset(a, x, sizeof(a)) #define huan printf("\n") #define debug(a,b) cout<<a<<" "<<b<<" "<<endl #define ffread(a) fastIO::read(a) using namespace std; typedef long long ll; typedef pair<int,int> pii; const int MAXN = 1000+10; const int MAXM = 500+10; int uN,vN; int g[MAXN][MAXM]; int linker[MAXM][MAXN]; bool used[MAXM]; int num[MAXM],limit; bool dfs(int u) { for(int v = 0; v < vN; v++) if(g[u][v] && !used[v]) { used[v] = true; if(linker[v][0] < limit) { linker[v][++linker[v][0]] = u; return true; } for(int i = 1; i <= linker[v][0]; i++) if(dfs(linker[v][i])) { linker[v][i] = u; return true; } } return false; } int hungary() { int res = 0,flag=0; for(int i = 0; i < vN; i++) linker[i][0] = 0; for(int u = 0; u < uN; u++) { memset(used,false,sizeof(used)); if(dfs(u)) res++; else { flag=1; break; } } return flag; } int main() { while(scanf("%d%d",&uN,&vN)!=EOF&&uN&&vN) { fillchar(g,0); getchar(); for(int i=0;i<uN;i++) { char s[2000]; gets(s); int len=strlen(s); int num=0,jishu=0; for(int j=len-1;j>=0;j--) { if(s[j]== ) { g[i][num]=1; num=jishu=0; } else if(s[j]>=0&&s[j]<=9) { num+=(int)(s[j]-0)*pow(10,jishu); jishu++; } else break; } } int l=0,r=uN; while(l<=r) { limit=(l+r)/2; //cout<<limit<<endl; if(!hungary()) r=limit-1; else l=limit+1; } printf("%d\n",r+1); } }

HDU 1669 二分圖多重匹配+二分