Task Schedule
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 1911 Accepted Submission(s): 687
Problem Description
Our geometry princess XMM has stoped her study in computational geometry to concentrate on her newly opened factory. Her factory has introduced M new machines in order to process the coming N tasks. For the i-th task, the factory has to start processing it at or after day Si, process it for Pi days, and finish the task before or at day Ei. A machine can only work on one task at a time, and each task can be processed by at most one machine at a time. However, a task can be interrupted and processed on different machines on different days.
Now she wonders whether he has a feasible schedule to finish all the tasks in time. She turns to you for help.
Now she wonders whether he has a feasible schedule to finish all the tasks in time. She turns to you for help.
Input
On the first line comes an integer T(T<=20), indicating the number of test cases.
You are given two integer N(N<=500) and M(M<=200) on the first line of each test case. Then on each of next N lines are three integers Pi, Si and Ei (1<=Pi, Si, Ei<=500), which have the meaning described in the description. It is guaranteed that in a feasible schedule every task that can be finished will be done before or at its end day.
You are given two integer N(N<=500) and M(M<=200) on the first line of each test case. Then on each of next N lines are three integers Pi, Si and Ei (1<=Pi, Si, Ei<=500), which have the meaning described in the description. It is guaranteed that in a feasible schedule every task that can be finished will be done before or at its end day.
Output
For each test case, print “Case x: ” first, where x is the case number. If there exists a feasible schedule to finish all the tasks, print “Yes”, otherwise print “No”.
Print a blank line after each test case.
Print a blank line after each test case.
Sample Input
2 4 3 1 3 5 1 1 4 2 3 7 3 5 9 2 2 2 1 3 1 2 2
Sample Output
Case 1: Yes Case 2: Yes
Author
allenlowesy
Source
Recommend
zhouzeyong
#include<iostream> #include<cstdio> #include<cstring> #include<queue> using namespace std; const int VM=1010; const int EM=500010; const int INF=0x3f3f3f3f; int n,m,cnt,head[VM]; int dep[VM],gap[VM],cur[VM],aug[VM],pre[VM]; //dep表示每个点的距离标记,gap表示距离为i的点有多少个,cur用于当前孤优化, //aug记录找到的增广路流量,path记录找到的增广路的路径。 struct Edge{ int u,v,nxt; int cap; }edge[EM]; void addedge(int cu,int cv,int cw){ edge[cnt].u=cu; edge[cnt].v=cv; edge[cnt].cap=cw; edge[cnt].nxt=head[cu]; head[cu]=cnt++; edge[cnt].u=cv; edge[cnt].v=cu; edge[cnt].cap=0; edge[cnt].nxt=head[cv]; head[cv]=cnt++; } int src,des; int SAP(){ int max_flow=0,u=src,v; int id,mindep; aug[src]=INF; pre[src]=-1; memset(dep,0,sizeof(dep)); memset(gap,0,sizeof(gap)); gap[0]=n; for(int i=0;i<=n;i++) cur[i]=head[i]; // 初始化当前弧为第一条弧 while(dep[src]<n){ int flag=0; if(u==des){ max_flow+=aug[des]; for(v=pre[des];v!=-1;v=pre[v]){ // 路径回溯更新残留网络 id=cur[v]; edge[id].cap-=aug[des]; edge[id^1].cap+=aug[des]; aug[v]-=aug[des]; // 修改可增广量,以后会用到 if(edge[id].cap==0) // 不回退到源点,仅回退到容量为0的弧的弧尾 u=v; } } for(int i=cur[u];i!=-1;i=edge[i].nxt){ v=edge[i].v; // 从当前弧开始查找允许弧 if(edge[i].cap>0 && dep[u]==dep[v]+1){ // 找到允许弧 flag=1; pre[v]=u; cur[u]=i; aug[v]=min(aug[u],edge[i].cap); u=v; break; } } if(!flag){ if(--gap[dep[u]]==0) /* gap优化,层次树出现断层则结束算法 */ break; mindep=n; cur[u]=head[u]; for(int i=head[u];i!=-1;i=edge[i].nxt){ v=edge[i].v; if(edge[i].cap>0 && dep[v]<mindep){ mindep=dep[v]; cur[u]=i; // 修改标号的同时修改当前弧 } } dep[u]=mindep+1; gap[dep[u]]++; if(u!=src) // 回溯继续寻找允许弧 u=pre[u]; } } return max_flow; } int main(){ //freopen("input.txt","r",stdin); int t,cases=0; scanf("%d",&t); while(t--){ scanf("%d%d",&n,&m); cnt=0; memset(head,-1,sizeof(head)); src=0; int sum=0,MAX=0,p,s,e; for(int i=1;i<=n;i++){ scanf("%d%d%d",&p,&s,&e); sum+=p; MAX=max(MAX,e); addedge(src,i,p); //源点与每个任务之间连一条边,容量为完成该任务所需处理次数 for(int j=s;j<=e;j++) //若第i个任务可以在Si至Ei天处理,则由该任务向这些天分别连一条边,容量为1,表示此任务每天只能被处理一次 addedge(i,n+j,1); } des=n+MAX+1; for(int i=1;i<=MAX;i++) addedge(n+i,des,m); //从每一天连一条到汇点的边,容量为机器数M,表示每天可以处理M个任务 n=des+1; if(SAP()==sum) //若求出的最大流等于所有任务需要处理的次数之和,说明能完成任务 printf("Case %d: Yes\n\n",++cases); else printf("Case %d: No\n\n",++cases); } return 0; }