UVA1515 pool ，玄学的最小割

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白书题，，，，不是很理解最小割u
多刷题吧，
以后应该就会了
这里写图片描述
#include<queue>#include<cstdio>#include<vector>#include<string>#include<cstring>#include<iostream>using namespace std;typedef long long LL;const int dx[]={ 0, 0,-1, 1};const int dy[]={-1, 1, 0, 0};const int INF=0x3f3f3f3f;const int N = 9999;int n,m,a[N],b[N];struct Dinic{    struct Edge{        int from,to,cap,flow;        Edge(int u,int v,int c,int f):            from(u),to(v),cap(c),flow(f){}    };    int n, s, t;    vector<Edge>edges;    vector< int>G[N]; //gragh    bool vis[N]; //use when bfs    int d[N],cur[N];//dist,now edge,use in dfs    inline void AddEdge(int from,int to,int cap){        edges.push_back(Edge(from,to,cap,0));        edges.push_back(Edge(to,from, 0 ,0));        int top = edges.size()  ;        G[from].push_back(top-2);        G[ to ].push_back(top-1);    }    inline void Init(int n){        this -> n= n ;        s = 0, t = n ;        edges.clear();        for (int i=0;i<=n;i++)G[i].clear();    }    inline bool BFS(){        memset(vis,0,sizeof(vis));        queue<int>Q;        Q.push(s);d[s]=0;vis[s]=1;        while (!Q.empty()){            int x=Q.front();Q.pop();            for (int i=0;i<G[x].size();i++){                Edge &e=edges[G[x][i]];                if (vis[e.to]||e.cap<=e.flow)continue;                vis[e.to]=1;                d[e.to]=d[x]+1;                Q.push(e.to);            }        }        return vis[t];    }    inline int DFS(const int& x,int a){        if (x==t||a==0){return a;}        int flow = 0, f;        for (int& i=cur[x];i<G[x].size();i++){            Edge& e=edges[G[x][i]];            if (d[x]+1!=d[e.to])continue;            if ((f=DFS(e.to,min(a,e.cap-e.flow)))<=0)continue;            e.flow += f;            edges[G[x][i]^1].flow-=f;//ϲߍ            flow+=f; a-=f;            if (!a) break;        }        return flow;    }    inline int maxFlow(){return maxFlow(s,t);}    inline int maxFlow(const int& s,const int& t){        int flow=0;        while(BFS()){            memset(cur,0,sizeof(cur));            flow += DFS(s,INF) ;            //printf("flow=%d\n",flow);        }        return flow;    }} g ;bool pool[99][99];int id[99][99];int main(){    //freopen("in.txt","r",stdin);    int T,n,m,d,f,b;    scanf("%d", &T);    for (char ch;T--;){        scanf("%d%d%d%d%d\n",&m,&n,&d,&f,&b);        for (int i=1;i<=n;i++){            for (int j=1;j<=m;j++){                scanf("%c",&ch);                pool[i][j] = ch=='#';                id[i][j] = (i-1)*m+j;            }            getchar() ;        }        int ans = 0;        g.Init( n*m+1);        for (int i=1;i<=n;i++){            for (int j=1;j<=m;j++){                if (i==1||i==n||j==1||j==m){                    g.AddEdge(g.s,id[i][j],INF);                    if (!pool[i][j]) ans += f ;                }else{//not at the bounder                    if(pool[i][j])g.AddEdge(g.s,id[i][j],d);                    else g.AddEdge(id[i][j],g.t,f);                }                for (int k=0;k<4;k++){                    int cx = i + dx[k];                    int cy = j + dy[k];                    if (cx<1||cx>n||cy<1||cy>m)continue;                    g.AddEdge(id[i][j],id[cx][cy],b);                }            }        }        printf("%d\n", ans + g.maxFlow());    }    return 0;}
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