hdu 1533 Going Home 费用流MCMF模板

题意：n个人和房子，每个人只能进入一个房子，且消费为两者曼哈顿距离，求n个人进入房子的最小花费。

建超源超汇，超源向人连边，超汇向房子连边，然后人向房子连边，跑MCMF即可

#include <bits/stdc++.h>#include <map>#include <set>#include <queue>#include <stack>#include <cmath>#include <time.h>#include <vector>#include <cstdio>#include <string>#include <iomanip>///cout << fixed << setprecision(13) << (double) x << endl;#include <cstdlib>#include <cstring>#include <iostream>#include <algorithm>using namespace std;#define lson l, mid, rt << 1#define rson mid + 1, r, rt << 1 | 1#define ls rt << 1#define rs rt << 1 | 1#define pi acos(-1.0)#define eps 1e-8#define Mp(a, b) make_pair(a, b)#define asd puts("asdasdasdasdasdf");typedef long long ll;typedef pair <int, int> pl;//typedef __int64 LL;const int inf = 0x3f3f3f3f;const int N = 440;const int st = N-9, ed = N-8;struct node{int v, w, c, nxt;//c--->cap  w--->cost(dis)}e[N*N*2];int cnt, n, m;int head[N];int dis[N];//费用看成距离int cap[N];//流量int cur[N];//当前弧int vis[N];queue <int> q;char mat[N][N];int flow, cost;vector <pl> H, M;void init(){cnt = 0;memset( head, -1, sizeof( head ) );memset( mat, inf, sizeof( mat ) );H.clear(), M.clear();}void add( int u, int v, int c, int w ){e[cnt].v = v;e[cnt].c = c;e[cnt].w = w;e[cnt].nxt = head[u];head[u] = cnt++;e[cnt].v = u;e[cnt].c = 0;e[cnt].w = -w;e[cnt].nxt = head[v];head[v] = cnt++;}bool spfa(){memset( dis, inf, sizeof( dis ) );memset( vis, 0, sizeof( vis ) );while( !q.empty() )q.pop();cap[st] = inf;cur[st] = -1;dis[st] = 0;q.push( st );while( !q.empty() ) {int u = q.front();q.pop();vis[u] = 0;for( int i = head[u]; ~i; i = e[i].nxt ) {int v = e[i].v, c = e[i].c, w = e[i].w;if( c && dis[v] > dis[u] + w ) {dis[v] = dis[u] + w;cap[v] = min( c, cap[u] );cur[v] = i;if( !vis[v] ) {vis[v] = 1;q.push(v);}}}}if( dis[ed] == inf )return 0;flow += cap[ed];cost += cap[ed] * dis[ed];for( int i = cur[ed]; ~i; i = cur[e[i^1].v] ) {e[i].c -= cap[ed];e[i^1].c += cap[ed];}return 1;}int MCMF(){flow = cost = 0;while( spfa() );return cost;}int main(){while( ~scanf("%d%d", &n, &m) ) {        if( n == m && n == 0 )            break;        init();        for( int i = 1; i <= n; ++i ) {            scanf("%s", mat[i]+1);            for( int j = 1; j <= m; ++j ) {                if( mat[i][j] == 'H' )                    H.push_back( Mp( i, j ) );                if( mat[i][j] == 'm' )                    M.push_back( Mp( i, j ) );            }        }        int hh = H.size(), mm = M.size();        for( int i = 0; i < hh; ++i ) {            add( st, i, 1, 0 );            int x1 = H[i].first, y1 = H[i].second;            for( int j = 0; j < mm; ++j ) {                int x2 = M[j].first, y2 = M[j].second;                int DIS =  abs( x1-x2 ) + abs( y1-y2 );                add( i, j+hh, 1, DIS );            }        }        for( int i = 0; i < mm; ++i )            add( i+hh, ed, 1, 0 );        int ans = MCMF();        printf("%d\n", ans);}return 0;}