POJ3762 The Bonus Salary! （费用流+离散化）

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <queue>
#include <cmath>
#include <vector>
#include <algorithm>
#include <limits.h>
using namespace std;
#define inf 1e8
#define maxn 4005
#define maxm 100005
int head[maxn],eid;
int dis[maxn];
bool vis[maxn];
int a[maxn];
int pre[maxn];
struct node
{
int u,v,cap,next,cost;
}eg[maxm];
void add(int u,int v,int cap,int cost)
{
eg[eid].u=u;
eg[eid].v=v;
eg[eid].cap=cap;
eg[eid].next=head[u];
eg[eid].cost=cost;
head[u]=eid++;
eg[eid].u=v;
eg[eid].v=u;
eg[eid].cap=0;
eg[eid].next=head[v];
eg[eid].cost=-cost;
head[v]=eid++;
}
bool spfa(int s,int t,int &flow,int &cost)
{
memset(vis,false,sizeof(vis));
for(int i=0;i<maxn;i++)
dis[i]=inf;
dis[s]=0;
vis[s]=true;
pre[s]=0;
a[s]=inf;
queue<int>q;
q.push(s);
while(!q.empty())
{
int u=q.front();
q.pop();
vis[u]=false;
for(int i=head[u];i!=-1;i=eg[i].next)
{
if(eg[i].cap&&dis[eg[i].v]>dis[u]+eg[i].cost)
{
dis[eg[i].v]=dis[u]+eg[i].cost;
pre[eg[i].v]=i;
a[eg[i].v]=min(a[u],eg[i].cap);
if(!vis[eg[i].v])
{
q.push(eg[i].v);
vis[eg[i].v]=true;
}
}
}
}
if(dis[t]==inf) return false;
flow+=a[t];
cost+=dis[t]*a[t];
int u=t;
while(u!=s)
{
eg[pre[u]].cap-=a[t];
eg[pre[u]^1].cap+=a[t];
u=eg[pre[u]].u;
}
return true;
}
int mincost(int s,int t)
{
int flow=0,cost=0;
while(spfa(s,t,flow,cost));
return cost;
}
void init()
{
memset(head,-1,sizeof(head));
eid=0;
}
int t1[maxn],t2[maxn],t3[maxn*2],t4[maxn*2],v[maxn];
int main()
{
//freopen("in.txt","r",stdin);
int n,m,x,y,z;
while(~scanf("%d%d",&n,&m))
{
init();
for(int i=0;i<n;i++)
{
scanf("%2d:%2d:%2d",&x,&y,&z);
t1[i]=x*10000+y*100+z;
t3[i*2]=t1[i];
scanf("%2d:%2d:%2d",&x,&y,&z);
t2[i]=x*10000+y*100+z;
t3[i*2+1]=t2[i];
scanf("%d",&v[i]);
}
sort(t3,t3+n*2);
int tot=1;
for(int i=0;i<n*2;i++)
{
t4[tot++]=t3[i];
while(i+1<n*2&&t3[i+1]==t3[i]) i++;
}
if(t4[tot-1]==t4[tot-2]) tot--;
for(int i=0;i<n;i++)
{
int flag=0;
for(int j=1;j<tot;j++)
{
if(t1[i]==t4[j])
{
t1[i]=j;
flag++;
}
if(t2[i]==t4[j])
{
t2[i]=j;
flag++;
}
if(flag==2) break;
}
}
for(int i=0;i<tot;i++)
add(i,i+1,m,0);
for(int i=0;i<n;i++)
add(t1[i],t2[i],1,-v[i]);
printf("%d\n",-mincost(0,tot));
}
return 0;
}