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最小费用最大流，EK中的BFS改成SPFA。。。

 

建图拿人和房子建，费用是人和房子坐标差值，加源点和汇点，求最小费用最大流即可。

 

我WA的厉害 = =。。。少加了句cost[to][from] = -cost[from][to];。。。

 

#include <cstdio>#include <cstdlib>#include <iostream>#include <string.h>#include <queue>#include <math.h>#include <limits.h>#define MAX 210using namespace std;typedef struct HOUSE{int x,y;int num;}HOUSE;HOUSE h[MAX],m[MAX];int n,M;int cap[MAX][MAX];int cost[MAX][MAX];int EKarpSPFA(int s,int t){int flow[MAX][MAX],a,c,i,dis[MAX];int pre[MAX],u,v;queue <int> Q;int inq[MAX];c = 0;memset(flow,0,sizeof(flow));while(1){for(i=s; i<=t; i++)dis[i] = INT_MAX;dis[s] = 0;memset(inq,0,sizeof(inq));Q.push(s); inq[s] = 1;while( !Q.empty() ){u = Q.front();Q.pop();inq[u] = 0;for(v=s; v<=t; v++)if( cap[u][v] > flow[u][v] && dis[v] > dis[u] + cost[u][v] ){dis[v] = dis[u] + cost[u][v];pre[v] = u;if( !inq[v] ){Q.push(v);inq[v] = 1;}}}if( dis[t] == INT_MAX )break;a = INT_MAX;for(u=t; u!=s; u=pre[u])if( cap[pre[u]][u] - flow[pre[u]][u] < a )a = cap[pre[u]][u] - flow[pre[u]][u];for(u=t; u!=s; u=pre[u]){flow[pre[u]][u] += a;flow[u][pre[u]] -= a;}c += dis[t]*a;}return c;}int main(){int i,house,man,k,from,to,ans;char str[MAX];while( scanf("%d%d",&n,&M) != EOF && n && M ){memset(cap,0,sizeof(cap));memset(cost,0,sizeof(cost));memset(h,'/0',sizeof(h));memset(m,'/0',sizeof(m));house = man = 1;for(i=0; i<n; i++){scanf("%s",str);for(k=0; k<M; k++){if( str[k] == 'H' ){h[house].x = i;h[house].num = house;h[house++].y = k;}if( str[k] == 'm' ){m[man].x = i;m[man].num = man;m[man++].y = k;}}}for(i=1; i<house; i++){cap[i][house+man-1] = 1;for(k=1; k<man; k++){from = k + house - 1;to = i;cap[from][to] = 1;cost[from][to] = abs( m[k].x - h[i].x ) + abs( m[k].y - h[i].y );cost[to][from] = -cost[from][to];}}for(k=1; k<man; k++)cap[0][k+house-1] = 1;ans = EKarpSPFA(0,man+house-1);printf("%d/n",ans);}return 0;}