hdu 3722 二分图 最优完备匹配 KM算法

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define CLR(arr, what) memset(arr, what, sizeof(arr))
#define maxn  305
#define INF  (1<<30)-1
int g[maxn][maxn];
int lx[maxn],ly[maxn],match[maxn];
bool visx[maxn],visy[maxn];
int slack[maxn];
int n,m;
char str[maxn][10001];
bool dfs(int cur){
visx[cur] = true;
for(int y=1;y<=m;y++){
if(visy[y])   continue;
int t=lx[cur]+ly[y]-g[cur][y];
if(t==0){
visy[y] = true;
if(match[y]==-1||dfs(match[y])){
match[y] = cur;
return true;
}
}
else if(slack[y]>t){
slack[y]=t;
}
}
return false;
}
int KM(){
CLR(match,-1);
CLR(ly,0);;
for(int i=1 ;i<=n;i++){
lx[i]=-INF;
for(int j=1;j<=m;j++)
if(g[i][j]>lx[i])   lx[i]=g[i][j];
}
for(int x=1;x<=n;x++){
for(int i=1;i<=m;i++)  slack[i]=INF;
while(true){
CLR(visx,false);
CLR(visy,false);
if(dfs(x))  break;
int d=INF;
for(int i=1;i<=m;i++){
if(!visy[i]&&d>slack[i])     d=slack[i];
}
for(int i=1;i<=n;i++){
if(visx[i])                  lx[i]-=d;
}
for(int i=1;i<=m;i++){
if(visy[i])                 ly[i]+=d;
else                        slack[i]-=d;
}
}
}
int result = 0;
for(int i = 1; i <=m; i++)
if(match[i]!=-1)
result += g[match[i]][i];
return result;
}

int solve(int i,int j)
{
if(i==j) return 0;
int len1=strlen(str[i]);
int len2=strlen(str[j]);

int P = len1-1;
int Q = 0;

while(P >= 0 && Q < len2 && str[i][P] == str[j][Q])
{
P--;
Q++;
}
return Q;

}
int main(){
while(scanf("%d",&n)!=EOF){
CLR(g,0);
m=n;
for(int i=1;i<=n;i++)
{
scanf("%s",str[i]);
}
for(int i=1;i<=n;i++)
{
for(int j=1;j<=n;j++)
{
int k=solve(i,j);
g[i][j]=k;
}
}
printf("%d\n",KM());
}
return 0;
}