[网络流24题]深海机器人问题（费用流）

题目

传送门

题解

和方格取数2实际上是一道题
输入非常的恶心，不想多说

代码

#include  
using namespace std;  

const int maxm=1050;  
const int maxn=1050;  
const int INF=0x3f3f3f3f;  
int s,t,tot,n,m;  
int a,b;  

struct Edge{  
    int to,nxt,cap,flow,cost;  
}edge[105000];  
int Head[maxn],tol;  
int mp[maxn][maxn];  
int pre[maxn],dis[maxn];  
bool vis[maxn];  

void addedge2(int u,int v,int cap,int cost){  
    edge[tol].to=v;  
    edge[tol].cap=cap;  
    edge[tol].cost=cost;  
    edge[tol].flow=0;  
    edge[tol].nxt=Head[u];  
    Head[u]=tol++;  
}  

void addedge(int u,int v,int cap,int cost){  
    addedge2(u,v,cap,cost);  
    addedge2(v,u,0,-cost);  
}  

bool spfa(int s,int t){  
    queue<int> q;  
    for(int i=0;ifalse;pre[i]=-1;  
    }  
    dis[s]=0;vis[s]=true;  
    q.push(s);  
    while(!q.empty()){  
        int u=q.front();  
        q.pop();  
        vis[u]=false;  
        for(int i=Head[u];i!=-1;i=edge[i].nxt){  
            int v=edge[i].to;  
            if (edge[i].cap>edge[i].flow&&dis[v]>dis[u]+edge[i].cost){  
                dis[v]=dis[u]+edge[i].cost;  
                pre[v]=i;  
                if (!vis[v]){  
                    vis[v]=true;  
                    q.push(v);  
                }  
            }  
        }  
    }  
    if (pre[t]==-1) return false;  
    return true;  
}  

int minCostMaxflow(int s,int t,int &cost){  
    int flow=0;  
    cost=0;  
    while(spfa(s,t)){  
        int Min=INF;  
        for(int i=pre[t];i!=-1;i=pre[edge[i^1].to])  
            if (Min>edge[i].cap-edge[i].flow)  
                Min=edge[i].cap-edge[i].flow;  
        for(int i=pre[t];i!=-1;i=pre[edge[i^1].to]){  
            edge[i].flow+=Min;  
            edge[i^1].flow-=Min;  
            cost+=edge[i].cost*Min;  
        }  
        flow+=Min;  
    }  
    return flow;  
}  

int main(){  
    //freopen("input.txt","r",stdin);  
    while(scanf("%d%d%d%d",&a,&b,&n,&m)!=EOF){  
        memset(Head,-1,sizeof(Head));  
        int cost,c=0,x,y;  
        tol=s=0;  
        t=(n+1)*(m+1)+1;  
        tot=t+1;  
        for(int i=0;i<=n;i++)  
            for(int j=0;j<=m;j++)  
                mp[i][j]=++c;  
        for(int i=0;i<=n;i++)  
        for(int j=0;jscanf("%d",&c);  
            addedge(mp[i][j],mp[i][j+1],1,-c);  
            addedge(mp[i][j],mp[i][j+1],INF,0);  
        }  
        for(int j=0;j<=m;j++)  
        for(int i=0;iscanf("%d",&c);  
            addedge(mp[i][j],mp[i+1][j],1,-c);  
            addedge(mp[i][j],mp[i+1][j],INF,0);  
        }  
        for(int i=0;iscanf("%d%d%d",&c,&x,&y);  
            addedge(s,mp[x][y],c,0);  
        }  
        for(int i=0;iscanf("%d%d%d",&c,&x,&y);  
            addedge(mp[x][y],t,c,0);  
        }  
        int flow;  
        flow=minCostMaxflow(s,t,cost);  
        printf("%d\n",-cost);  
    }  
    return 0;  
}