[POJ3249] Test for Job [longest path on topological sort +dag]

Source: Internet
Author: User

Given a point-weighted Dag, find the longest path with a 0-node to a 0-node dimension

Turn the point right into Benquan (at the same time multi-source conversion into a single source): Edge u->v of the weight of w[v], so that the degree of 0 of the node weights will be omitted, a new point 0 into the degree of 0 points u connected to the edge, the weight is w[u], so that only 0 is the point of 0 degrees.

First, the topology is sorted, and then the longest path is obtained by using the features of the DAG topology ordering.

1#include <iostream>2#include <algorithm>3#include <cstring>4#include <cmath>5#include <cstdio>6 using namespacestd;7typedefLong LongLL;8 9template<classT>voidRead (T &x) {TenRegisterintc = GetChar (), F =1; x =0; One    while(!isdigit (c)) {if(c = ='-') F =-1; c =GetChar ();} A    while(IsDigit (c)) x = x*Ten+ (c& the), C =GetChar (); -X *=F; - } the Const intN =100005; - structedge{intV, W, next;} g[n* -]; - intN, M, S, Head[n], tot, ind[n], out[N], w[n]; LL Dis[n], ans =-123023423423; - voidToposort (ints) { +   intTopo[n], cnt =0; -TOPO[++CNT] =0; +    for(intK =0; K <= CNT; ++k) A      for(inti = head[topo[k]]; I i =G[i].next) { at       intv =g[i].v; -ind[v]--; -       if(ind[v]==0) topo[++cnt] =v; -     } -memset (DIS,0xc0,sizeof(dis)); Dis[s] =0; -    for(intK =0; K <= CNT; ++k) in      for(inti = head[topo[k]]; I i =G[i].next) { -       intv = g[i].v, w =G[I].W; toDIS[V] = max (dis[topo[k]]+W, Dis[v]); +     } - } the  *InlinevoidAddintUintVintW) { $G[++tot].v=v, G[tot].w=w, g[tot].next=head[u];head[u]=tot;Panax Notoginsengind[v]++, out[u]++; - } the  + intMainvoid){ A    while(SCANF ("%d%d", &n, &m) = =2){ theMemset (Head,0,sizeof(head)); tot=0; Memset (Ind,0,sizeof(Ind)); Memset out,0,sizeof( out)); +Ans =0xc0c0c0c0c0c0c0c0; -      for(inti =1; I <= N; ++i) read (W[i]); $      for(intU, V, i =1; I <= m; ++i) { $ Read (U), read (v); - Add (U, V, w[v]); -     }  the      for(inti =1; I <= N; ++i) { -       if(!ind[i]) Add (0, I,w[i]);Wuyi     } the Toposort (s); -      for(inti =1; I <= N; ++i) { Wu       if(! out[i]) ans =Max (ans, dis[i]); -     } Aboutcout << ans <<'\ n'; $   } -   return 0; -}
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[POJ3249] Test for Job [longest path on topological sort +dag]

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