HDU2255-奔小康赚大钱-二分图最大权值匹配-KM算法

/*--------------------------------------------------------------------------------------*/

#include <algorithm>
#include <iostream>
#include <cstring>
#include <ctype.h>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <string>
#include <queue>
#include <stack>
#include <cmath>
#include <set>
#include <map>

//debug function for a N*M array
#define debug_map(N,M,G) printf("\n");for(int i=0;i<(N);i++)\
{for(int j=0;j<(M);j++){\
printf("%d",G[i][j]);}printf("\n");}
//debug function for int,float,double,etc.
#define debug_var(X) cout<<#X"="<<X<<endl;
#define LL long long
const int INF = 0x3f3f3f3f;
const LL LLINF = 0x3f3f3f3f3f3f3f3f;
/*--------------------------------------------------------------------------------------*/
using namespace std;

int N,M,T;
const int maxn = 310;
int nx,ny;
int g[maxn][maxn];
int linker[maxn],lx[maxn],ly[maxn];
int slack[maxn];
bool visx[maxn],visy[maxn];
bool DFS(int x)
{
visx[x] = true;
for(int y=0;y<ny;y++)
{
if(visy[y]) continue;
int tmp = lx[x] + ly[y] - g[x][y];
if(tmp == 0)
{
visy[y] = true;
if(linker[y] == -1 || DFS(linker[y]))
{
linker[y] = x;
return true;
}
}
else if(slack[y] > tmp) slack[y] = tmp;
}
return false;
}
int KM()
{
memset(linker,-1,sizeof linker);
memset(ly,0,sizeof ly);
for(int i=0;i<nx;i++)
{
lx[i] = -INF;
for(int j=0;j<ny;j++)   lx[i] = max(lx[i],g[i][j]);
}
for(int x=0;x<nx;x++)
{
for(int i=0;i<ny;i++) slack[i] = INF;
while(true)
{
memset(visx,false,sizeof visx);
memset(visy,false,sizeof visy);
if(DFS(x)) break;
int d = INF;
for(int i=0;i<ny;i++) if(!visy[i] && d > slack[i]) d = slack[i];
for(int i=0;i<nx;i++) if(visx[i]) lx[i] -= d;
for(int i=0;i<ny;i++)
{
if(visy[i]) ly[i] += d;
else slack[i] -= d;
}
}
}
int res = 0;
for(int i=0;i<ny;i++) if(linker[i] != -1) res += g[linker[i]][i];
return res;
}
int main()
{
while(~scanf("%d",&N))
{
for(int i=0;i<N;i++)
{
for(int j=0;j<N;j++)
{
scanf("%d",&g[i][j]);
}
}
nx = ny = N;
printf("%d\n",KM());
}
}