# hdu 3722 Card Game (有向环覆盖，拆点，二分图最佳匹配，KM算法)

Posted by 111qqz on Thursday, June 2, 2016

## TOC

hdu 3722题目链接

``````/* ***********************************************
Author :111qqz
Created Time :2016年06月02日 星期四 23时37分55秒
File Name :code/hdu/3722.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=205;
int n;
char st[N][1005];
int w[N][N];
int lx[N],ly[N];
bool visx[N],visy[N];
int slk[N];
int solve(string a,string b)
{
int la = a.length();
int lb = b.length();
int len = min(la,lb);
int res = 0 ;
for ( int i = 0 ; i < len ; i++)
{
if (b[i]==a[la-1-i]) res++;
else break;
}
return res;
}

bool find( int u)
{
// cout<<"u:"<<u<<endl;
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;
{
return true;
}
}else if (tmp<slk[v]) slk[v] = tmp;
}
return false;
}
int KM()
{
ms(lx,0);
ms(ly,0);

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++)
{
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++)

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

while (~scanf("%d",&n))
{
for ( int i = 1 ; i <= n ; i++) scanf("%s",st[i]);

ms(w,0);

for ( int i = 1 ; i <= n ; i++)
for ( int j = 1 ; j <= n ; j++)
if (i!=j) w[i][j] = solve(string(st[i]),string(st[j]));

//   for ( int i = 1 ; i <= n ; i++)
//	for ( int j = 1 ; j <= n ; j++) if (i!=j) cout<<"w[i][j]:"<<w[i][j]<<endl;

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

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

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