【PowerOJ1753&网络流24题】分配问题（KM）

题意：

思路：费用流可做

最好的算法是KM板子

 #include<bits/stdc++.h>
 using namespace std;
 typedef long long ll;
 typedef unsigned int uint;
 typedef unsigned long long ull;
 typedef long double ld;
 typedef pair<int,int> PII;
 typedef pair<ll,ll> Pll;
 typedef vector<int> VI;
 typedef vector<PII> VII;
 typedef pair<ll,ll>P;
 #define N  500
 #define M  1000000
 #define INF 1e9
 #define fi first
 #define se second
 #define MP make_pair
 #define pb push_back
 #define pi acos(-1)
 #define mem(a,b) memset(a,b,sizeof(a))
 #define rep(i,a,b) for(int i=(int)a;i<=(int)b;i++)
 #define per(i,a,b) for(int i=(int)a;i>=(int)b;i--)
 #define lowbit(x) x&(-x)
 #define Rand (rand()*(1<<16)+rand())
 #define id(x) ((x)<=B?(x):m-n/(x)+1)
 #define ls p<<1
 #define rs p<<1|1

 const ll MOD=1e9+,inv2=(MOD+)/;
       double eps=1e-;
       int dx[]={-,,,};
       int dy[]={,,-,};

 int lx[N],ly[N],lk[N],slk[N],pre[N],vy[N],w[N][N],
     py,n,m,x,y,i,j,d,p;

 int read()
 {
    int v=,f=;
    char c=getchar();
    while(c<||<c) {if(c=='-') f=-; c=getchar();}
    while(<=c&&c<=) v=(v<<)+v+v+c-,c=getchar();
    return v*f;
 }

 void solve1()
 {
     rep(i,,n)
      rep(j,,n) w[i][j]=-w[i][j];
     rep(i,,n)
     {
         rep(j,,n) slk[j]=INF,vy[j]=;
         for(lk[py=]=i;lk[py];py=p)
         {
             vy[py]=; d=INF; x=lk[py];
             rep(y,,n)
              if(!vy[y])
              {
                  if(lx[x]+ly[y]-w[x][y]<slk[y]) slk[y]=lx[x]+ly[y]-w[x][y],pre[y]=py;
                  if(slk[y]<d) d=slk[y],p=y;
              }
             rep(y,,n)
              if(vy[y]) lx[lk[y]]-=d,ly[y]+=d;
               else slk[y]-=d;

         }
         for(;py;py=pre[py]) lk[py]=lk[pre[py]];
     }
     ll ans=;
     rep(i,,n) ans+=lx[i]+ly[i];
     printf("%lld\n",-ans);
 }

 void solve2()
 {
     mem(lx,);
     mem(ly,);
     mem(lk,);
     rep(i,,n)
      rep(j,,n) w[i][j]=-w[i][j];
     rep(i,,n)
     {
         rep(j,,n) slk[j]=INF,vy[j]=;
         for(lk[py=]=i;lk[py];py=p)
         {
             vy[py]=; d=INF; x=lk[py];
             rep(y,,n)
              if(!vy[y])
              {
                  if(lx[x]+ly[y]-w[x][y]<slk[y]) slk[y]=lx[x]+ly[y]-w[x][y],pre[y]=py;
                  if(slk[y]<d) d=slk[y],p=y;
              }
             rep(y,,n)
              if(vy[y]) lx[lk[y]]-=d,ly[y]+=d;
               else slk[y]-=d;

         }
         for(;py;py=pre[py]) lk[py]=lk[pre[py]];
     }
     ll ans=;
     rep(i,,n) ans+=lx[i]+ly[i];
     printf("%lld\n",ans);
 }

 int main()
 {
     //freopen("1.in","r",stdin);
     n=read();
     rep(i,,n)
      rep(j,,n) w[i][j]=read();
     solve1();
     solve2();
 }