A - Going Home

A - Going Home

https://vjudge.net/contest/385979#problem

0到所有🐎，🐎到🏠，房子到cnt+1连边，其中🐎和🏠的代价为曼哈顿距离

#include<iostream>
#include<cstdio>
#include<queue>
#include<algorithm>
#include<cmath>
#include<ctime>
#include<set>
#include<map>
#include<stack>
#include<cstring>
#define inf 2147483647
#define ls rt<<1
#define rs rt<<1|1
#define lson ls,nl,mid,l,r
#define rson rs,mid+1,nr,l,r
#define N 100010
#define For(i,a,b) for(long long i=a;i<=b;i++)
#define p(a) putchar(a)
#define g() getchar()

using namespace std;
long long n,m,s,t,x,y,v,w,maxflow,mincost,tot,cnt;
long long head[N],pre[N],last[N],flow[N],d[N];
bool vis[N];
char c[510][510];
struct node{
    long long n;
    long long v;
    long long w;
    long long next;
}e[N];

struct Node{
    long long x;
    long long y;
}a[N];

queue<long long>q;
void in(long long &x){
    long long y=1;
    char c=g();x=0;
    while(c<'0'||c>'9'){
        if(c=='-')y=-1;
        c=g();
    }
    while(c<='9'&&c>='0'){
        x=(x<<1)+(x<<3)+c-'0';c=g();
    }
    x*=y;
}
void o(long long x){
    if(x<0){
        p('-');
        x=-x;
    }
    if(x>9)o(x/10);
    p(x%10+'0');
}

void push(long long x,long long y,long long v,long long w){
    e[tot].n=y;
    e[tot].v=v;
    e[tot].w=w;
    e[tot].next=head[x];
    head[x]=tot++;
}

bool spfa(long long s,long long t){
    memset(d,0x7f,sizeof(d));
    memset(flow,0x7f,sizeof(flow));
    memset(vis,0,sizeof(vis));
    q.push(s);
    vis[s]=1;
    d[s]=0;
    pre[t]=-1;
    while(!q.empty()){
        long long now=q.front();
        q.pop();
        vis[now]=0;
        for(long long i=head[now];i!=-1;i=e[i].next)
            if(e[i].v>0&&d[e[i].n]>d[now]+e[i].w){
                d[e[i].n]=d[now]+e[i].w;
                pre[e[i].n]=now;
                last[e[i].n]=i;
                flow[e[i].n]=min(flow[now],e[i].v);
                if(!vis[e[i].n]){
                    vis[e[i].n]=1;
                    q.push(e[i].n);
                }
            }
    }
    return pre[t]!=-1;
}

void MCMF(long long s,long long t){
    maxflow=mincost=0;
    while(spfa(s,t)){
        long long now=t;
        maxflow+=flow[t];
        mincost+=flow[t]*d[t];
        while(now!=s){
            e[last[now]].v-=flow[t];
            e[last[now]^1].v+=flow[t];
            now=pre[now];
        }
    }
}

long long Abs(long long x){
    return x>0?x:-x;
}

signed main(){
    while(cin>>n>>m && (n+m)){
        memset(head,-1,sizeof(head));
        cnt=tot=0;
        For(i,1,n){
            For(j,1,m){
                cin>>c[i][j];
                if(c[i][j]=='m'){
                    a[++cnt].x=i;
                    a[cnt].y=j;
                }
            }
        }
        For(i,1,n){
            For(j,1,m){
                if(c[i][j]=='H'){
                    a[++cnt].x=i;
                    a[cnt].y=j;
                }
            }
        }
        For(i,1,cnt/2){
            push(0,i,1,0);
            push(i,0,0,0);
            push(i+cnt/2,cnt+1,1,0);
            push(cnt+1,i+cnt/2,0,0);
        }
        For(i,1,cnt/2)
            For(j,cnt/2+1,cnt){
                long long temp=Abs(a[i].x-a[j].x)+Abs(a[i].y-a[j].y);
                push(i,j,1,temp);
                push(j,i,0,-temp);
            }

        MCMF(0,cnt+1);
        o(mincost);p('\n');
    }
    return 0;
}