Build: From the source point to the first layer of the edge, the first layer of the day to use out how many napkins, the second layer of how many napkins are needed for the day, so pay attention to the purchase of the napkin edge capacity for infinity, to start from the source point to the second level point, every day there may be surplus, Nodes that are represented in the first layer as flowing into the second day. See the code, the first time to write the cost flow, do not know the template is right ...
#include <iostream>#include<algorithm>#include<cstdio>#include<cstring>#include<cmath>#include<ctime>#include<cstdlib>#include<queue>using namespacestd;template<Const int_n,Const int_m>structedge{structEdge_base {intTo,next,w,c;} E[_M]; intCnt,p[_n]; Edge () {clear ();} intStartConst intx) {returnp[x];} voidInsertConst intXConst intYConst intZConst intZZ) {e[++cnt].to=y; E[CNT].NEXT=P[X]; E[cnt].w=z; E[cnt].c=zz; p[x]=cnt;return ; } voidClear () {cnt=1, Memset (P,0,sizeof(p)); } edge_base&operator[](Const intx) {returne[x];};intn,dis[110000],sss,ttt,cur[110000],a[110000];intCost,flow;BOOLvisited[110000]; Edge<110000,210000>e;BOOLSPFA (Const intS) { inti,t,temp; Queue<int>Q; memset (Dis,0x3f,sizeof(Dis)); Dis[s]=0; Visited[s]=true; Q.push (S); while(!Q.empty ()) {T=q.front (), Q.pop (); visited[t]=false; for(I=e.start (t); i;i=E[i].next) {Temp=e[i].to; if(E[I].W && dis[t]+e[i].c<Dis[temp]) {Dis[temp]=dis[t]+e[i].c; if(!Visited[temp]) {Visited[temp]=true; Q.push (temp); } } } } returndis[ttt]!=0x3f3f3f3f;}intDfs (Const intSConst intBK) { if(S==TTT)returnBK; Visited[s]=true; intrest=K; for(int&i=cur[s];i;i=E[i].next) { if(!visited[e[i].to] && dis[s]+e[i].c==dis[e[i].to] &&E[I].W) { intflow=Dfs (E[i].to,min (REST,E[I].W)); Cost+=flow*e[i].c; E[I].W-=flow; E[i^1].w+=flow; if((Rest-=flow) <=0) Break; } } if(bk==rest) dis[s]=0x3f3f3f3f; Visited[s]=false; returnbk-Rest;} Pair<int,int>Dinic () { while(SPFA (SSS)) {memcpy (CUR,E.P,sizeof(cur)); Flow+=dfs (SSS,0x3f3f3f3f); } returnMake_pair (flow,cost);}intMain () {Freopen ("napkin.in","R", stdin); Freopen ("Napkin.out","W", stdout); intI,NEWN,TS,CS,TF,CF; scanf ("%d",&N); for(i=1; i<=n;++i) scanf ("%d",&A[i]); scanf ("%d%d%d%d%d",&newn,&ts,&cs,&tf,&CF); SSS=n+n+1; ttt=sss+1; for(i=1; i<=n;++i) {E.insert (sss,i,a[i],0), E.insert (I,sss,0,0); E.insert (i+n,ttt,a[i],0), E.insert (Ttt,i+n,0,0); E.insert (Sss,i+n,0x3f3f3f3f, newn), E.insert (I+n,sss,0,-newn); if(i!=n) E.insert (i,i+1,0x3f3f3f3f,0), E.insert (i+1I0,0); if(i+tf<=n) E.insert (I,i+tf+n,0x3f3f3f3f, CF), E.insert (I+tf+n,i,0,-CF); if(i+ts<=n) E.insert (I,i+ts+n,0x3f3f3f3f, CS), E.insert (I+ts+n,i,0,-CS); } printf ("%d\n", Dinic (). second); return 0;}
[cogs461] [Network Flow 24 # #] Napkins [network flow, minimum cost maximum flow]