HDU 3572Task Schedule（网络流）

题意：i-th task，start time>=si,time of processing is pi days,it should be finished before ei days.

Tip1.one machine compute one task at one time;

Tip2.one task should be done on one machine at one time;

思路：设sink和source，每一个时间虚拟为一个点，source与每一个task连一条容量为pi的边，

每一个task向它的时间段的每一个点连一条容量为1的边（题目的限制Tip2），最后每一个时间点向

sink连一条容量为the number of machine（Tip1）。

#include<iostream>
#include<cstring>
#include<algorithm>
#include<queue>
#include<cstdio>
#define inf 0x7fffffff
using namespace std;
int n,m;
int sum;
int st,ed;
bool cmp(int a,int b)
{
	return a<b;
}
struct nodee
{
	int v,next,flow;
}e[505*505*2];
int head[505*2],cnt;
class Dinic
{
	public:
		int spath()
		{
			queue<int>q;
			while(!q.empty()) q.pop();
			memset(dis,-1,sizeof(dis));
			dis[st]=0;
			q.push(st);
			while(!q.empty())
			{
				int u=q.front();
				q.pop();
				for(int i=head[u];i+1;i=e[i].next)
				{
					int v=e[i].v;
					if(dis[v]==-1&&e[i].flow>0)
					{
						dis[v]=dis[u]+1;
						q.push(v); 
					}
				}
			}
			return dis[ed]!=-1;
		}
		int Min(int a,int b)
		{
			if(a<b) return a;
			return b;
		}
		int dfs(int u,int flow)
		{
			int cost=0;
			if(u==ed) return flow;
			for(int i=head[u];i+1;i=e[i].next)
			{
				int v=e[i].v;
				if(dis[v]==dis[u]+1&&e[i].flow>0)
				{
					int min=dfs(v,Min(e[i].flow,flow-cost));
					if(min>0)
					{
						e[i].flow-=min;
						e[i^1].flow+=min;
						cost+=min;
						if(cost==flow) break;
					}
					else dis[v]=-1;
				}
			}
			return cost;
		}
		int result()
		{
			int res=0;
			while(spath())
			{
				res+=dfs(st,inf);
			}
			return res;
		}
	private:
		int dis[505*2];
}dinic;
void Init()
{
	memset(head,-1,sizeof(head));
	cnt=0;
}
void add(int a,int b,int c)
{
	e[cnt].v=b;
	e[cnt].flow=c;
	e[cnt].next=head[a];
	head[a]=cnt++;
	
	e[cnt].v=a;
	e[cnt].flow=0;
	e[cnt].next=head[b];
	head[b]=cnt++;
}
void Input()
{
	int maxx=-1;
	int minn=inf;
	st=0;
	sum=0;
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)
	{
		int p,s,e;
		scanf("%d%d%d",&p,&s,&e);
		sum+=p;
	    add(st,i,p);
		if(e>maxx) maxx=e;
		if(s<minn) minn=s;
		for(int j=s;j<=e;j++)
		{
			add(i,n+j,1);
		}
	}
	ed=n+maxx+1;
	for(int i=n+minn;i<=n+maxx;i++)
	add(i,ed,m);
}
void treatment(int ca)
{
	cout<<"Case "<<ca<<": ";
	int k=dinic.result();
	//cout<<k<<endl;
    if(k==sum) cout<<"Yes"<<endl;
    else cout<<"No"<<endl;
    cout<<endl;
}
int main()
{
	int t,ca=1;
	scanf("%d",&t);
	while(t--)
	{
		Init();
		Input();
		treatment(ca++);
	}
	return 0;
}