Poj3013-big Christmas tree-Shortest circuit

Test Instructions: give a graph, each node has the right value, each edge also has the cost. A tree is required to make the total cost minimal. The cost of each side of the tree is defined as the child node weights and x this side cost.

Practice: analysis shows that the final answer is the weight of all nodes x to the distance of the root node. It is possible to know the minimum cost when the distance is shortest.

So with the Dijkstra+ Priority queue optimization can be done. This problem has some card time. Finally, it is also important to use long long, which n=0 and n=1.

1 /*--------------------------------------------------------------------------------------*/2 //Helica ' s header3 //Second Edition4 //2015.11.75 //6#include <algorithm>7#include <iostream>8#include <cstring>9#include <ctype.h>Ten#include <cstdlib> One#include <cstdio> A#include <vector> -#include <string> -#include <queue> the#include <stack> -#include <cmath> -#include <Set> -#include <map> +  - //Debug function for a n*m array + #defineDebug_map (n,m,g) printf ("\ n"); for (int i=0;i< (N); i++) A{ for(intj=0;j< (M); J + +){ atprintf"%d", G[i][j]);} printf"\ n");}  - //Debug function for int,float,double,etc. - #defineDebug_var (X) cout<< #X "=" <<X<<endl; - /*--------------------------------------------------------------------------------------*/ - using namespacestd; -  in Const intMAXN = 5e4+Ten; - Const Long LongINF =0x3f3f3f3f3f3f3f3f; to intn,m,t,s; +  - structQnode the { *     intv,c; $Qnode (int_v=0,int_c=0): V (_v), C (_c) {}Panax Notoginseng     BOOL operator< (ConstQnode &r)Const -{returnC>r.c;} the }; +  A structEdge the { +     intTo,next; -     intCost ; $}edge[4*MAXN]; $  - intHEAD[MAXN],TOL,WEIGHT[MAXN]; - Long LongDIS[MAXN]; the BOOLVIS[MAXN]; -Priority_queue<qnode>que;Wuyi  the voidDijkstra (intNintstart) - { Wumemset (Vis,false,sizeofvis); -      for(intI=1; i<=n;i++) Dis[i] =INF; AboutDis[start] =0; $      while(!que.empty ()) Que.pop (); -  -Que.push (Qnode (Start,0)); - Qnode cur; A      while(!que.empty ()) +     { theCur =que.top (); - Que.pop (); $         intU =cur.v; the         if(Vis[u])Continue; theVis[u] =true; the  the          for(intI=head[u];~i;i=edge[i].next) -         { in             intv =edge[i].to; the             intCost =Edge[i].cost; the             //printf ("u:%d v:%d cost:%d\n", u,v,cost); About             if(!vis[v] && dis[v]>dis[u]+Cost ) the             { theDIS[V] = dis[u]+Cost ; the Que.push (Qnode (v,dis[v)); +             } -         } the     }Bayi } the  the voidAdd_edge (intUintVintCost ) - { -Edge[tol].to =u; theEdge[tol].next =Head[v]; theEdge[tol].cost =Cost ; theHEAD[V] = tol++; the  -Edge[tol].to =v; theEdge[tol].next =Head[u]; theEdge[tol].cost =Cost ; theHead[u] = tol++;94 } the  the intMain () the {98scanf"%d",&T); About      while(t--) -     {101scanf"%d%d",&n,&M);102          for(intI=1; i<=n;i++) scanf ("%d",&weight[i]);103memset (head,-1,sizeofhead);104memset (Vis,false,sizeofvis); theTol =0;106          for(intI=0; i<m;i++)107         {108             inta,b,c;109scanf"%d%d%d",&a,&b,&c); the Add_edge (a,b,c);111         } the         if(n==0|| n==1)113         { theprintf"0\n"); the             Continue; the         }117Dijkstra (N,1);118 119         Long LongAns =0; -         BOOLFlag =true;121          for(intI=2; i<=n;i++)122         {123             if(Dis[i] = =INF)124             { theFlag =false;126                  Break;127             } -             Else129Ans + = weight[i]*Dis[i]; the         }131  the         if(!flag) printf ("No answer\n");133         Elseprintf"%lld\n", ans);134     }135}

Poj3013-big Christmas tree-Shortest circuit