HDU 3046-Pleasant sheep and big big wolf(网络流_最小割)
来源:互联网 发布:恐怖整人软件 编辑:程序博客网 时间:2024/05/01 19:52
Pleasant sheep and big big wolf
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2254 Accepted Submission(s): 946
Problem Description
In ZJNU, there is a well-known prairie. And it attracts pleasant sheep and his companions to have a holiday. Big big wolf and his families know about this, and quietly hid in the big lawn. As ZJNU ACM/ICPC team, we have an obligation to protect pleasant sheep and his companions to free from being disturbed by big big wolf. We decided to build a number of unit fence whose length is 1. Any wolf and sheep can not cross the fence. Of course, one grid can only contain an animal.
Now, we ask to place the minimum fences to let pleasant sheep and his Companions to free from being disturbed by big big wolf and his companions.
Now, we ask to place the minimum fences to let pleasant sheep and his Companions to free from being disturbed by big big wolf and his companions.
Input
There are many cases.
For every case:
N and M(N,M<=200)
then N*M matrix:
0 is empty, and 1 is pleasant sheep and his companions, 2 is big big wolf and his companions.
For every case:
N and M(N,M<=200)
then N*M matrix:
0 is empty, and 1 is pleasant sheep and his companions, 2 is big big wolf and his companions.
Output
For every case:
First line output “Case p:”, p is the p-th case;
The second line is the answer.
First line output “Case p:”, p is the p-th case;
The second line is the answer.
Sample Input
4 61 0 0 1 0 00 1 1 0 0 02 0 0 0 0 00 2 0 1 1 0
Sample Output
Case 1:4
题意:在一个n*m的草原上,羊是1,狼是2,要安长度为1的栅栏,要求用最小的栅栏保证羊不被狼吃掉。
思路:建立一个超级源点与狼相连,长度为inf,建立一个超级汇点与羊相连,长度为inf,然后剩下的格子相连长度为1,然后找。
这个图真心怪怪的,一开始用搜索找四个方向,愣是不对,最后只好用笨办法,一个一个来喽。
#include <stdio.h>#include <string.h>#include <stdlib.h>#include <iostream>#include <algorithm>#include <set>#include <queue>#include <map>using namespace std;const int inf=0x3f3f3f3f;int head[1000100],num[100010],d[100010],pre[100010],cur[100010],mp[310][310];int n,m,cnt,nv,s,t;int jx[]={1,0,-1,0};int jy[]={0,1,0,-1};struct node{ int u,v,cap; int next;}edge[10000010];void add(int u, int v, int cap){ edge[cnt].v=v; edge[cnt].cap=cap; edge[cnt].next=head[u]; head[u]=cnt++; edge[cnt].v=u; edge[cnt].cap=0; edge[cnt].next=head[v]; head[v]=cnt++;}void bfs(){ memset(d,-1,sizeof(d)); memset(num,0,sizeof(num)); queue<int >q; q.push(t); d[t]=0; num[0]=1; while(!q.empty()) { int i; int u=q.front(); q.pop(); for(i=head[u]; i!=-1; i=edge[i].next) { int v=edge[i].v; if(d[v]==-1) continue; d[v]=d[u]+1; num[d[v]]++; q.push(v); } }}void isap(){ memcpy(cur,head,sizeof(cur)); int flow=0, u=pre[s]=s, i; bfs(); while(d[s]<nv) { if(u==t) { int f=inf, pos; for(i=s; i!=t; i=edge[cur[i]].v) { if(f>edge[cur[i]].cap) { f=edge[cur[i]].cap; pos=i; } } for(i=s; i!=t; i=edge[cur[i]].v) { edge[cur[i]].cap-=f; edge[cur[i]^1].cap+=f; } flow+=f; u=pos; } for(i=cur[u]; i!=-1; i=edge[i].next) { if(d[edge[i].v]+1==d[u]&&edge[i].cap) break; } if(i!=-1) { cur[u]=i; pre[edge[i].v]=u; u=edge[i].v; } else { if(--num[d[u]]==0) break; int mind=nv; for(i=head[u]; i!=-1; i=edge[i].next) { if(mind>d[edge[i].v]&&edge[i].cap) { mind=d[edge[i].v]; cur[u]=i; } } d[u]=mind+1; num[d[u]]++; u=pre[u]; } } printf("%d\n",flow);}int main(){ int i, j,k; int tt=1; while(~scanf("%d%d",&n,&m)) { cnt=0; s=0; t=n*m+1; nv=t+1; memset(head,-1,sizeof(head)); for(i=1; i<=n; i++) { for(j=1; j<=m; j++) { scanf("%d",&mp[i][j]); if(mp[i][j]==1) add(s,(i-1)*m+j,inf); if(mp[i][j]==2) add((i-1)*m+j,t,inf); if(i!=1) add((i-1)*m+j,(i-2)*m+j,1);// 与上面的点相连 if(i!=n) add((i-1)*m+j,i*m+j,1);//与下面的点相连 if(j!=1) add((i-1)*m+j,(i-1)*m+j-1,1);//与左边的点相连 if(j!=m) add((i-1)*m+j,(i-1)*m+j+1,1);//与右边的点相连 } } printf("Case %d:\n",tt++); isap(); } return 0;}
0 0
- HDU 3046-Pleasant sheep and big big wolf(网络流_最小割)
- hdu 3046 Pleasant sheep and big big wolf //最小割
- hdu 3046 Pleasant sheep and big big wolf (最小割)
- hdu 3046 Pleasant sheep and big big wolf(最小割)
- HDU 3046 Pleasant sheep and big big wolf 最小割
- HDU 3046 Pleasant sheep and big big wolf | 最小割
- hdu 3046 Pleasant sheep and big big wolf 最小割
- Pleasant sheep and big big wolf (hdu 3046 最小割)
- HDU - 3046 Pleasant sheep and big big wolf(最小割)
- hdu 3046 Pleasant sheep and big big wolf(最小割)
- HDU 3046Pleasant sheep and big big wolf(网络流之最小割)
- hdu 3046 Pleasant sheep and big big wolf 网络流
- HDU 3046 Pleasant sheep and big big wolf 最小割==最大流(喜羊羊)
- hdu 3046 Pleasant sheep and big big wolf【最大流Dinic--------最小割】
- hdoj 3046 Pleasant sheep and big big wolf 【最小割】
- 【网络流】HDU3046 Pleasant sheep and big big wolf (最小割/最大流)
- hdu 3046 Pleasant sheep and big big wolf(最小割)
- HDU 3046 Pleasant sheep and big big wolf(最小割)
- 使用MySql创建表时发生Can't create table 'xx' (errno: 150)的可能原因。
- iOS 高德地图API不能定位及INVALID_USER_SCODE问题
- jsoup url 跳转
- 在kettle里编写javascript代码操作数据
- 保存Volley的缓存图片到本地,当网络不通的时候,访问本地的图片
- HDU 3046-Pleasant sheep and big big wolf(网络流_最小割)
- ad系统内存线程使用情况
- Windows下SVN版本库迁移
- 利用predis操作redis方法大全
- 代码同行评审不可或缺的东西
- JVM监控工具-jrmc
- usb控制传输
- ffmpeg安装第三方编码器(encoder)库,ffmpeg编码h264(完)
- PullToRefresh使用详解(三)--实现异步加载的下拉刷新列表