【codevs1033】蚯蚓的游戏问题

#include<iostream>
#include<cstring>
#include<cstdio>
#include<queue>
using namespace std;

const int max_n=50;
const int max_m=50;
const int max_N=(max_n+2*max_m-1)*max_n+4;
const int max_M=max_n*max_m*4;
const int max_e=max_M*2;
const int inf=1e9;

int n,m,k,food,x1,x2,y1,y2,cnt,maxflow,maxcost,N;
int next[max_e],point[max_N],v[max_e],remain[max_e],c[max_e],tot;
int last[max_N],dis[max_N],vis[max_N];
queue <int> q;

inline void addedge(int x,int y,int cap,int z){
++tot; next[tot]=point[x]; point[x]=tot; v[tot]=y; remain[tot]=cap; c[tot]=z;
++tot; next[tot]=point[y]; point[y]=tot; v[tot]=x; remain[tot]=0; c[tot]=-z;
}

inline int addflow(int s,int t){
int ans=inf,now=t;
while (now!=s){
ans=min(ans,remain[last[now]]);
now=v[last[now]^1];
}

now=t;
while (now!=s){
remain[last[now]]-=ans;
remain[last[now]^1]+=ans;
now=v[last[now]^1];
}
return ans;
}

inline bool bfs(int s,int t){
memset(dis,128,sizeof(dis));
memset(vis,0,sizeof(vis));
dis[s]=0;
vis[s]=true;
while (!q.empty()) q.pop();
q.push(s);

while (!q.empty()){
int now=q.front(); q.pop();
vis[now]=false;
for (int i=point[now];i!=-1;i=next[i])
if (dis[v[i]]<dis[now]+c[i]&&remain[i]){
dis[v[i]]=dis[now]+c[i];
last[v[i]]=i;
if (!vis[v[i]]){
vis[v[i]]=true;
q.push(v[i]);
}
}
}

if (dis[t]<0) return false;
int flow=addflow(s,t);
maxflow+=flow;
maxcost+=flow*dis[t];
return true;
}

inline void major(int s,int t){
maxflow=0; maxcost=0;
while (bfs(s,t));
}

int main(){
tot=-1;
memset(point,-1,sizeof(point));
memset(next,-1,sizeof(next));

scanf("%d%d%d",&n,&m,&k);
N=(n+2*m-1)*n+4;
for (int i=1;i<=n;++i)
for (int j=1;j<=m+i-1;++j){
scanf("%d",&food);
++cnt;
x1=cnt*2+1; x2=cnt*2+2;
addedge(x1,x2,1,food);
if (i==1)
addedge(2,x1,inf,0);
if (i!=n){
y1=(cnt+m+i-1)*2+1; y2=(cnt+m+i)*2+1;
addedge(x2,y1,inf,0);
addedge(x2,y2,inf,0);
}
else
addedge(x2,N-1,inf,0);
}
addedge(1,2,k,0);
addedge(N-1,N,k,0);

major(1,N);
printf("%d\n",maxcost);
}