luogu3778/bzoj4898 Hotel (floyd+ score planning +SPFA)

First Floyd to find out the shortest distance between every two points, and then find out from a point to buy to a point to sell the maximum benefit

The problem is to find the one with the greatest ratio of the ring

So do score planning, two points out the answer R, turn Benquan into W[i]-r*l[i], and then do SPFA sentence positive ring on the line

(originally want to lazy use Floyd sentence positive ring, result T)

1#include <bits/stdc++.h>2 #definePA pair<int,int>3 #defineCLR (a,x) memset (A,x,sizeof (a))4 using namespacestd;5typedefLong Longll;6 Const intmaxn= the, maxm=10010, maxk=1010;7 Constll inf=1e15;8 9 Inline LL Rd () {Tenll x=0;CharC=getchar ();intneg=1; One      while(c<'0'|| C>'9'){if(c=='-') neg=-1; c=GetChar ();} A      while(c>='0'&&c<='9') x=x*Ten+c-'0', c=GetChar (); -     returnx*neg; - } the  - intW[MAXN][MAXN]; - intSELL[MAXN][MAXK],BUY[MAXN][MAXK]; - intN,M,K,CNT[MAXN]; + ll DIS[MAXN][MAXN],D[MAXN][MAXN],DD[MAXN]; - BOOLINQ[MAXN]; +queue<int>Q; A  at BOOLSPFA (ints) { -      while(!q.empty ()) Q.pop (); -dd[s]=0; Q.push (s); cnt[s]=1; -      while(!Q.empty ()) { -         intP=q.front (); inq[p]=0; -         //printf ("%d%d%d\n", p,cnt[p],dd[p]); in Q.pop (); -          for(intb=1; b<=n;b++){ to             if(D[p][b]==-inf)Continue; +             if(dd[b]<=dd[p]+D[p][b]) { -dd[b]=dd[p]+D[p][b]; the                 if(Inq[b])Continue; *                 if(++cnt[b]>n)return 1; $ Q.push (b);Panax Notoginsenginq[b]=1; -             } the         } +}return 0; A } the  +InlineBOOLjudge (ll R) { -     //printf ("%lld:\n", r); $      for(intI=1; i<=n;i++){ $          for(intj=1; j<=n;j++) -D[i][j]= (dis[i][j]==-1)?-inf:w[i][j]-r*Dis[i][j]; -     } the     BOOLRe=0; -CLR (CNT,0); CLR (INQ,0);Wuyi      for(intI=1; i<=n;i++) dd[i]=-inf; the      for(intI=1; i<=n&&!re;i++){ -         if(!cnt[i]) re|=SPFA (i); Wu     } -     returnre; About } $  - intMain () { -     //freopen ("", "R", stdin); -     inti,j,k; AN=rd (), M=rd (), k=Rd (); +      for(i=1; i<=n;i++){ the          for(j=1; j<=k;j++){ -Buy[i][j]=rd (), sell[i][j]=Rd (); $         } the     } the      for(i=1; i<=n;i++){ the          for(j=1; j<=n;j++){ the             if(I==J)Continue; -              for(k=1; k<=k;k++){ in                 if(sell[j][k]==-1|| buy[i][k]==-1)Continue; theW[i][j]=max (w[i][j],sell[j][k]-buy[i][k]); the             } About         } the     } theCLR (dis,-1); the      for(i=1; i<=m;i++){ +         intA=rd (), B=rd (), c=Rd (); -dis[a][b]=C; the     }Bayi      for(i=1; i<=n;i++){ the          for(j=1; j<=n;j++){ the             if(dis[j][i]==-1)Continue; -              for(k=1; k<=n;k++){ -                 if(dis[i][k]==-1)Continue; the                 if(dis[j][k]==-1|| dis[j][k]>dis[j][i]+Dis[i][k]) thedis[j][k]=dis[j][i]+Dis[i][k]; the             } the         } -     } the     //for (i=1;i<=n;i++) for (j=1;j<=n;j++) printf ("%d-%d,%lld,%lld\n", I,j,dis[i][j],w[i][j]); the      thell l=0, r=inf,ans=0;94      while(l<=S) { the         intM=l+r>>1; the         if(judge (m)) ans=m,l=m+1; the         Elser=m-1;98     } Aboutprintf"%lld\n", ans); -     return 0;101}

luogu3778/bzoj4898 Hotel (floyd+ score planning +SPFA)