BZOJ1221[HNOI2001] Software Development

BZOJ1221[HNOI2001] Software Development

Test instructions

N days, the daily need to disinfect the AI bar towel, this disinfectant towel used after a day must be disinfected before use. Disinfection methods There are two, a mode of disinfection needs a day, a cost fa,b way of disinfection needs B days, a cost FB, buy a new towel for the cost of f (new towel is disinfected, the same day can be used), to find the minimum cost. n≤1000

Exercises

Cost flow. Split every day into X and Y. s to all X-linked side of the towel, all y to the T-side of the towel, the flow of the need to towel 0. Xi to the Yi+a, said a way disinfection, Xi to yi+b with the edge, said the B mode disinfection, s to all Y side, to buy a new, Xi to xi+1 with the edge, that the day before useless to get the next days use. Reflection: The key to cost flow is to seize the "traffic first".

Code:

1#include <cstdio>2#include <cstring>3#include <algorithm>4#include <queue>5 #defineInc (I,J,K) for (int i=j;i<=k;i++)6 #defineMAXN 30007 #defineINF 0X3FFFFFFF8 using namespacestd;9 Ten structe{intF,t,c,w,n;}; E es[maxn* +];intESS,G[MAXN]; OneInlinevoidPeintFintTintCintW) { AEs[++ess]= (e) {f,t,c,w,g[f]}; g[f]=ess; Es[++ess]= (e) {t,f,0,-w,g[t]}; g[t]=ess; - } - voidInit () {ess=-1; memset (g,-1,sizeof(g));} the intD[MAXN],FR[MAXN];BOOLINQ[MAXN]; Queue <int>Q; - BOOLSPFA (intSintt) { -      while(!q.empty ()) Q.pop (); memset (INQ,0,sizeof(INQ)); memset (d,-1,sizeof(d)); -inq[s]=1; d[s]=0; Q.push (s); fr[s]=-1; +      while(!Q.empty ()) { -         intX=q.front (); Q.pop (); inq[x]=0; +          for(inti=g[x];i!=-1; i=es[i].n)if(es[i].c&& (d[es[i].t]==-1|| d[es[i].t]>d[x]+ES[I].W)) { AD[ES[I].T]=D[X]+ES[I].W; Fr[es[i].t]=i;if(!inq[es[i].t]) inq[es[i].t]=1, Q.push (es[i].t); at         } -     } -     returnd[t]!=-1; - } - intAdvancedintSintt) { -     intA=inf,c=0; in      for(inti=fr[t];i!=-1; I=FR[ES[I].F]) a=min (a,es[i].c); -      for(inti=fr[t];i!=-1; I=FR[ES[I].F]) es[i].c-=a,es[i^1].c+=a,c+= (A *ES[I].W); to     returnC; + } - intMaxflowmincost (intSintt) { the     intC=0; while(SPFA (s,t)) c+=advanced (s,t);returnC; * } $ intn,a,b,f,fa,fb,s,t,x;Panax Notoginseng intMain () { -scanf"%d%d%d%d%d%d", &AMP;N,&AMP;A,&AMP;B,&AMP;F,&AMP;FA,&AMP;FB); s=0; t=2*n+1; init (); theInc (I,1, N) scanf ("%d", &x), PE (S,I,X,0), PE (N+I,T,X,0); +Inc (I,1, N) { A         if(i+a<n) PE (i,n+i+a+1, INF,FA);if(i+b<n) PE (i,n+i+b+1, INF,FB); the         if(i<n) PE (i,i+1Inf0); PE (s,i+n,inf,f); +     } -printf"%d", Maxflowmincost (s,t));return 0; $}

20160602

BZOJ1221[HNOI2001] Software Development