hdu 3395 Special Fish (二分图最佳匹配,KM算法)

Posted by 111qqz on Wednesday, June 1, 2016

TOC

hdu 3395题目链接

题意:鱼,一些鱼认为自己是汉子,然后他会去和他认为是妹子的鱼啪啪啪,然后被啪啪啪的妹子就会产卵? 卵的val是它parent的val的异或。给出n,为鱼的数量,然后给出一个n*n的 mat,a[i][j]==1表示第i条鱼认为第j条鱼是妹子。问卵的最大val之和是多少。需要注意的是:每条鱼最多可以去和一个妹子啪,并且可以作为妹子被啪一次(这两个是独立的。。。) (Each fish can attack one other fish and can only be attacked once)

思路:二分图最佳匹配,KM算法,2A.

/* ***********************************************
Author :111qqz
Created Time :2016年06月01日 星期三 20时38分58秒
File Name :code/hdu/3395.cpp
************************************************ */

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>
#define fst first
#define sec second
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define ms(a,x) memset(a,x,sizeof(a))
typedef long long LL;
#define pi pair < int ,int >
#define MP make_pair

using namespace std;
const double eps = 1E-8;
const int dx4[4]={1,0,0,-1};
const int dy4[4]={0,-1,1,0};
const int inf = 0x3f3f3f3f;
const int N=105;
int n;
int w[N][N];
char a[N][N];
int val[N];
bool visx[N],visy[N];
int link[N];
int lx[N],ly[N];
int slk[N];



bool find( int u)
{
    visx[u] = true;

    for ( int v = 1 ; v <= n ; v++)
    {
    if (visy[v]) continue;

    int tmp = lx[u] + ly[v] - w[u][v];

    if (tmp==0)
    {
        visy[v] = true;
        if (link[v]==-1||find(link[v]))
        {
        link[v] =  u;
        return true;
        }
    }
    else if (tmp<slk[v]) slk[v] = tmp;
    }
    return false;
}
int KM()
{
    ms(lx,0);
    ms(ly,0);
    ms(link,-1);

    for ( int i = 1 ; i <= n ; i++)
    for ( int j = 1 ; j <= n ; j++)
        lx[i] = max(lx[i],w[i][j]);

   // for ( int i = 1 ; i <= n ; i++) if (lx[i]==0) return -1;

    for ( int i = 1 ; i <= n ; i++)
    {
    ms(slk,0x3f);

    while (1)
    {
        ms(visx,false);
        ms(visy,false);

        if (find(i)) break;

        int d = inf;

        for ( int j = 1 ; j <= n ; j++) if (!visy[j]&&slk[j]<d) d = slk[j];

        for ( int j = 1 ; j <= n ; j++) if (visx[j]) lx[j]-=d;
        for ( int j = 1 ; j <= n ; j++) if (visy[j]) ly[j]+=d; else slk[j]-=d;
    }

    }

    int res = 0 ;
    for ( int i = 1 ; i <= n ; i++)
    if (link[i]>-1) res += w[link[i]][i];

    return res;
}
int main()
{
    #ifndef  ONLINE_JUDGE 
    freopen("code/in.txt","r",stdin);
  #endif

    while (scanf("%d",&n)!=EOF)
    {
        if (n==0) break;
        ms(w,0);
        for ( int i = 1 ; i <= n ; i++) scanf("%d",&val[i]);

        for ( int i = 1 ; i <= n ; i++)
        for ( int j = 1 ; j <= n ;j++) w[i][j] = val[i] ^ val[j];
	    

        for ( int i = 1 ; i <= n ; i++) scanf("%s",a[i]+1);
        for ( int i = 1 ; i <= n ; i++)
        for ( int j  = 1; j <= n ; j++)
        {
            if (a[i][j]=='0') w[i][j]=0;
        }

        int ans = KM();
        printf("%d\n",ans);


	    
    }

	

  #ifndef ONLINE_JUDGE  
  fclose(stdin);
  #endif
    return 0;
}

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