POJ 1273 Drainage Ditches 最大流
来源:互联网 发布:档案管理 源码 编辑:程序博客网 时间:2024/05/22 13:45
Drainage Ditches
Time Limit: 1000MS Memory Limit: 10000KTotal Submissions: 50942 Accepted: 19336
Description
Every time it rains on Farmer John's fields, a pond forms over Bessie's favorite clover patch. This means that the clover is covered by water for awhile and takes quite a long time to regrow. Thus, Farmer John has built a set of drainage ditches so that Bessie's clover patch is never covered in water. Instead, the water is drained to a nearby stream. Being an ace engineer, Farmer John has also installed regulators at the beginning of each ditch, so he can control at what rate water flows into that ditch.
Farmer John knows not only how many gallons of water each ditch can transport per minute but also the exact layout of the ditches, which feed out of the pond and into each other and stream in a potentially complex network.
Given all this information, determine the maximum rate at which water can be transported out of the pond and into the stream. For any given ditch, water flows in only one direction, but there might be a way that water can flow in a circle.
Farmer John knows not only how many gallons of water each ditch can transport per minute but also the exact layout of the ditches, which feed out of the pond and into each other and stream in a potentially complex network.
Given all this information, determine the maximum rate at which water can be transported out of the pond and into the stream. For any given ditch, water flows in only one direction, but there might be a way that water can flow in a circle.
Input
The input includes several cases. For each case, the first line contains two space-separated integers, N (0 <= N <= 200) and M (2 <= M <= 200). N is the number of ditches that Farmer John has dug. M is the number of intersections points for those ditches. Intersection 1 is the pond. Intersection point M is the stream. Each of the following N lines contains three integers, Si, Ei, and Ci. Si and Ei (1 <= Si, Ei <= M) designate the intersections between which this ditch flows. Water will flow through this ditch from Si to Ei. Ci (0 <= Ci <= 10,000,000) is the maximum rate at which water will flow through the ditch.
Output
For each case, output a single integer, the maximum rate at which water may emptied from the pond.
Sample Input
5 41 2 401 4 202 4 202 3 303 4 10
Sample Output
50
Source
USACO 93
[Submit] [Go Back] [Status] [Discuss]
最大流简单例题 Dinic算法
#include <iostream>#include <string.h>#include <stdio.h>using namespace std;const int INF=2e9;const int mm=999;const int mn=999;int node,s,t,edge;int ver[mm],flow[mm],next[mm];int head[mn],work[mn],dis[mn],q[mn];void init(int _node,int _s,int _t){ node=_node, s=_s, t=_t; for(int i=0;i<node;++i) head[i]=-1; edge=0;}void addedge(int u,int v,int c){ ver[edge]=v,flow[edge]=c,next[edge]=head[u],head[u]=edge++; ver[edge]=u,flow[edge]=0,next[edge]=head[v],head[v]=edge++;}bool Dinic_bfs(){ int i,u,v,l,r=0; for(i=0;i<node;++i) dis[i]=-1; dis[ q[r++]=s ] = 0; for(l=0;l<r;l++) { for(i=head[ u=q[l] ]; ~i ;i=next[i]) if(flow[i] && dis[ v=ver[i] ]<0) { dis[ q[r++]=v ]=dis[u]+1; if(v==t) return 1; } } return 0;}int Dinic_dfs(int u,int exp){ if(u==t) return exp; for(int &i=work[u],v,temp; ~i ;i=next[i]) { if(flow[i] && dis[ v=ver[i] ]==dis[u]+1 && ( temp=Dinic_dfs(v,min(exp,flow[i])) )>0) { flow[i]-=temp; flow[i^1]+=temp; return temp; } } return 0;}int Dinic_flow(){ int ans=0,res,i; while(Dinic_bfs()) { for(i=0;i<node;++i) work[i]=head[i]; while( res=Dinic_dfs(s,INF) ) ans+=res; } return ans;}int main(){ int n,m,u,v,c; while(scanf("%d%d",&m,&n)!=EOF) { init(n+1,1,n); while(m--) { scanf("%d%d%d",&u,&v,&c); addedge(u,v,c); } printf("%d\n",Dinic_flow()); } return 0;}
- poj 1273 Drainage Ditches 网络最大流
- 【最大流】北大 poj 1273 Drainage Ditches
- POJ-1273 Drainage Ditches【最大流】
- poj 1273 Drainage Ditches--最大流--Dinic
- poj 1273Drainage Ditches 最大流
- poj 1273 Drainage Ditches--最大流--sap
- poj 1273 Drainage Ditches---maxflow最大流
- poj - 1273 - Drainage Ditches(最大流)
- poj 1273 Drainage Ditches(最大流)
- poj-1273 Drainage Ditches 最大流
- POJ 1273 Drainage Ditches 最大流
- poj 1273 Drainage Ditches (最大流Dinic)
- POJ 1273 Drainage Ditches 最大流
- POJ 1273 Drainage Ditches(最大流)
- POJ 1273 Drainage Ditches 最大流 dinic
- POJ 1273 Drainage Ditches 最大流
- POJ 1273 Drainage Ditches (网络最大流)
- poj 1273 最大流 Drainage Ditches
- iframe关于jquery的使用
- GDB 命令详细解释【转】
- EditText输入后不能删除的问题
- 外挂、反外挂很好用的工具---olldbg
- NDK开发学习- findLibrary returned null错误
- POJ 1273 Drainage Ditches 最大流
- Spring MVC 国际化
- XCode上搭建coos2dx + lua开发项目
- deb 安装时提示有系统DS_Store 文件 ,删除
- java对象转换成为json数据
- 在ubuntu12.04中安装中文输入法fcitx
- LUA脚本
- Objective-C中使用@try处理异常
- 『openframeworks』shader制作三角形马赛克效果