HDU 1532 基础EK Drainage Ditches
2015-07-27 10:39
543 查看
Drainage Ditches
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 11744 Accepted Submission(s): 5519
[align=left]Problem Description[/align]
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.
[align=left]Input[/align]
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.
[align=left]Output[/align]
For each case, output a single integer, the maximum rate at which water may emptied from the pond.
[align=left]Sample Input[/align]
5 4
1 2 40
1 4 20
2 4 20
2 3 30
3 4 10
[align=left]Sample Output[/align]
50
[align=left]Source[/align]
USACO 93
[align=left]Recommend[/align]
lwg | We have carefully selected several similar problems for you: 1533 3338 1569 3572 3416
#include<stdio.h> #include<string.h> #include<iostream> #include<algorithm> #include<queue> using namespace std; int dp[400][400],pre[400]; const int tmin=999999999; int maxflow; void EK(int start,int end,int n){ while(1){ queue<int>q; q.push(1); int minflow=tmin; memset(pre,0,sizeof(pre)); while(!q.empty()){ int u=q.front(); q.pop(); for(int i=1;i<=n;i++){ if(dp[u][i]>0&&!pre[i]){ pre[i]=u; q.push(i); } } } if(pre[end]==0) break; for(int i=end;i!=start;i=pre[i]){ minflow=min(dp[pre[i]][i],minflow); } for(int i=end;i!=start;i=pre[i]){ dp[pre[i]][i]-=minflow; dp[i][pre[i]]+=minflow; } maxflow+=minflow; } } int main(){ int n,m; while(scanf("%d%d",&m,&n)!=EOF){ memset(dp,0,sizeof(dp)); memset(pre,0,sizeof(pre)); int u,v,w; for(int i=1;i<=m;i++){ scanf("%d%d%d",&u,&v,&w); dp[u][v]+=w; } maxflow=0; EK(1,n,n); printf("%d\n",maxflow); } return 0; }
相关文章推荐
- Source Insight函数调用关系显示设置http://blog.csdn.net/duanbeibei/article/details/24395777
- singnal 13 was raised
- gdb基本调试(cp:http://blog.csdn.net/feixiaoxing/article/details/7199643)
- 在linux中使用vi 打开文件时,能显示行号吗?http://zhidao.baidu.com/link?url=km4N-VLhK1DtSUOexgWMiZ73tp7R91g2UhZ15eTZv4
- Ubuntu 中sendmail 的安装、配置与发送邮件的具体实现
- Fibonacci Again
- AirPlay、DLNA、Miracast三大无线技术介绍
- 中小企业TurboMail邮件系统建设方案指导
- linux 进程等待 wait 、 waitpid
- hd2674 N!Again
- [leetcode-11]container with most water(C)
- 【LeetCode】70 - Climbing Stairs
- RAII手法封装互斥锁
- assign、copy、retain、weak、strong的区别与联系
- DataInputStream和DataOutputStream操作基本数据类型的流
- Fine-Grained Histopathological Image Analysis via Robust Segmentation and Large-Scale Retrieval文章总结
- Contains Duplicate
- hdu 5289 - Assignment(2015 Multi-University Training Contest 1 )单调队列+RMQ+树状数组
- Could not find a storyboard named 'MainStoryboard'
- 如何让gmail不过滤垃圾邮件