费用流SPFA版

#include <queue> #include <vector> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <iostream> #include <algorithm> using namespace std; typedef long long ll; typedef unsigned long long ull; const int inf=0x3f3f3f3f; const ll INF=0x3f3f3f3f3f3f3f3fll; const int maxn=410; const int maxm=100010; int head[maxn],eid,dis[maxn],pre[maxn],a[maxn]; bool vis[maxn]; struct node{ int u,v,cap,next,cost; }eg[maxm]; void addedge(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 A[210],B[210],C[210],tmp[maxn]; int main(){ int T,n,m; scanf("%d",&T); while(T--){ scanf("%d%d",&n,&m); init(); int len=0; for(int i=0;i<n;i++) scanf("%d%d%d",&A[i],&B[i],&C[i]),tmp[len++]=A[i],tmp[len++]=B[i]; sort(tmp,tmp+len); int kkk=1; for(int i=1;i<len;i++) if(tmp[i]!=tmp[i-1]) tmp[kkk++]=tmp[i]; addedge(0,1,m,0);addedge(kkk,kkk+1,m,0); for(int i=1;i<kkk;i++) addedge(i,i+1,inf,0); for(int i=0;i<n;i++){ int a=lower_bound(tmp,tmp+kkk,A[i])-tmp+1; int b=lower_bound(tmp,tmp+kkk,B[i])-tmp+1; addedge(a,b,1,-C[i]); } printf("%d\n",-mincost(0,kkk+1)); } return 0; }