100 lines
3.2 KiB
C++
100 lines
3.2 KiB
C++
#include<iostream>
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#include<algorithm>
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#include<stdio.h>
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#include<string.h>
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#include<math.h>
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#include<queue>
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#define MAXN 3005
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#define MAXM 500005
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#define oo 1000000007
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#define ll long long
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using namespace std;
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struct Dinic
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{
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struct node
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{
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int x,y,c,next;
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}line[MAXM];
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int Lnum,_next[MAXN],dis[MAXN];
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void initial(int n)
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{
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for (int i=0;i<=n;i++) _next[i]=-1;
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Lnum=-1;
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}
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void addline(int x,int y,int c)
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{
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line[++Lnum].next=_next[x],_next[x]=Lnum;
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line[Lnum].x=x,line[Lnum].y=y,line[Lnum].c=c;
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line[++Lnum].next=_next[y],_next[y]=Lnum;
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line[Lnum].x=y,line[Lnum].y=x,line[Lnum].c=0;
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}
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bool BFS(int s,int e)
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{
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queue<int> Q;
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while (!Q.empty()) Q.pop();
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memset(dis,0,sizeof(dis));
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dis[s]=1;
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Q.push(s);
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while (!Q.empty())
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{
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int h,k;
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h=Q.front(),Q.pop();
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if (h==e) return dis[e];
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for (k=_next[h];k!=-1;k=line[k].next)
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if (line[k].c && !dis[line[k].y])
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dis[line[k].y]=dis[h]+1,Q.push(line[k].y);
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}
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return false;
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}
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int dfs(int x,int flow,int e)
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{
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if (x==e) return flow;
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int temp,cost=0;
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for (int k=_next[x];k!=-1;k=line[k].next)
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if (line[k].c && dis[line[k].y]==dis[x]+1)
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{
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temp=dfs(line[k].y,min(flow-cost,line[k].c),e);
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if (temp)
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{
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line[k].c-=temp,line[k^1].c+=temp;
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cost+=temp;
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if (flow==cost) return cost;
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}else dis[line[k].y]=-1;
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}
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return cost;
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}
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int MaxFlow(int s,int e)
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{
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int MaxFlow=0;
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while (BFS(s,e))
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MaxFlow+=dfs(s,oo,e);
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return MaxFlow;
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}
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}T;
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int main()
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{
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int R,C,i,j,s,e,v,sum;
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while (~scanf("%d%d",&R,&C))
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{
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T.initial(R*C+5);
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s=R*C+1,e=R*C+2,sum=0;
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for (i=0;i<R;i++)
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for (j=0;j<C;j++)
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{
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scanf("%d",&v),sum+=v;
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if ((i+j)%2)
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{
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T.addline(s,i*C+j,v);
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if (i) T.addline(i*C+j,(i-1)*C+j,oo);
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if (j) T.addline(i*C+j,i*C+j-1,oo);
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if (i!=R-1) T.addline(i*C+j,(i+1)*C+j,oo);
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if (j!=C-1) T.addline(i*C+j,i*C+j+1,oo);
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}
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else
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T.addline(i*C+j,e,v);
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}
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printf("%d\n",sum-T.MaxFlow(s,e));
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}
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return 0;
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}
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