POJ no.3680 Intervals

2016-06-01 22:01:39

Title Link: POJ no.3680 intervals

Main topic:

Given n weighted intervals, a maximum of one point m can be repeated and a selection method is obtained to make the maximum

Solution:

Cost flow

Modeling:

The endpoints of the interval are connected in accordance with the sub-weight flow 1, and each point needs to be connected to a 0-weighted flow of infinity as a skip

Note the place:

100,000 points must be no, see me unique discrete Dafa

1 //intervals (POJ no.3680)2 //Cost Flow3#include <stdio.h>4#include <algorithm>5#include <queue>6 using namespacestd;7 Const intmaxn=410;8 intt,n,k;9 intHASH[MAXN];Ten intA[MAXN]; One intW[MAXN]; A structEdge - { -     intto ; the     int  from; -     intCost ; -     intflow; -     intNext; + Edge () {} -Edgeint  from,intTo,intCostintFlowintNext): from( from), to, cost, flow, next (next) {} + }; AEdge n[maxn*Ten]; at intCNT; - intLen; - intNow ; - intHEAD[MAXN]; - BOOLVIS[MAXN]; - intDIST[MAXN]; in intPRE[MAXN]; -Queue <int>Q; to voidInsertintXintYintZintCost ) + { -n[++cnt]=Edge (X,y,cost,z,head[x]); thehead[x]=CNT; *N[++cnt]=edge (Y,x,-cost,0, Head[y]); $head[y]=CNT;Panax Notoginseng     return ; - } the voidSPFA (intSintt) + { AFill (DIST,DIST+MAXN,100000); the Q.push (s); +vis[s]=1; -dist[s]=0; $      while(!q.empty ()) $     { -now=Q.front (); - Q.pop (); thevis[now]=0; -          for(intI=head[now];i;i=n[i].next)Wuyi         { the             if(n[i].flow>0) -             { Wu                 if(dist[n[i].to]>dist[now]+n[i].cost) -                 { Aboutdist[n[i].to]=dist[now]+N[i].cost; $pre[n[i].to]=i; -                     if(!vis[n[i].to]) -                     { -vis[n[i].to]=1; A Q.push (n[i].to); +                     } the                 } -             } $         } the     } the      for(intI=pre[t];i;i=pre[n[i]. from]) the     { then[i].flow--; -n[i^1].flow++; in     } the     return ; the } About intMincost_flow (intSintTintnum) the { the     intans=0; the      while(num--) +     { - SPFA (s,t); theans+=Dist[t];Bayi     } the     return-ans; the } - intMain () - { thescanf"%d",&T); the      while(t--) the     { theCnt=1; -Fill (HEAD,HEAD+MAXN,0); thescanf"%d%d",&n,&K); the          for(intI=1; i<=n;i++) the         {94scanf"%d%d", &a[i*2-1],&a[i*2]); thescanf"%d",&w[i]); thehash[i*2-1]=a[i*2-1]; thehash[i*2]=a[i*2];98         } AboutSort (hash+1, hash+2*n+1); -Len=unique (hash+1, hash+2*n+1)-hash-1;101          for(intI=1; i<=n*2; i++)102         {103A[i]=lower_bound (hash+1, hash+len+1, A[i])-Hash;104             if(! (i&1)) Insert (a[i-1],a[i],1,-w[i/2]); the         }106          for(intI=1; i<len;i++) Insert (i,i+1,100000,0);107Insert (len,len+1K0);108Insert0,1K0);109printf"%d\n", Mincost_flow (0, len+1, K)); the     }111}

POJ no.3680 Intervals