No root minimum tree chart template

1#include <iostream>2 using namespacestd;3#include <cstdio>4#include <cstring>5 #defineMAXN 10056 #defineINF 0x7f7f7f7f7 typedef __int64 type;8 structNode//the right and the vertex of the edge9 {Ten     intu, v; One type W; A}EDGE[MAXN *MAXN]; - intPRE[MAXN], ID[MAXN], VIS[MAXN], N, M, POS; -Typeinch[MAXN];//min. pre[v] is the starting point of the edge theType Directed_mst (intRootintVintE) - { -Type RET =0;//total weight of minimum tree diagram -      while(true) +     { -         inti; +         //1. Find the minimum incoming edge for each node A          for(i =0; i < V; i++) at             inch[I] = INF;//Initialize to Infinity -          for(i =0; i < E; i++)//Traverse each edge -         { -             intU =edge[i].u; -             intv =edge[i].v; -             if(EDGE[I].W <inch[v] && u! = V)//description of the edge record with a lower weight in vertex v in             { -PRE[V] = u;//node U points to v to                 inch[v] = EDGE[I].W;//Minimum incoming Edge +                 if(U = = root)//this point is the actual starting point. -pos =i; the             } *         } $          for(i =0; i < V; i++)//determine if there is a minimum tree chartPanax Notoginseng         { -             if(i = =root) the                 Continue; +             if(inch[I] = =INF) A                 return-1;//In addition to the root is a little into the edge, then the root can not reach it indicates that it is independent of the point must not constitute a tree chart the         } +         //2. Find a ring -         intCNT =0;//number of record rings $memset (ID,-1,sizeof(ID)); $memset (Vis,-1,sizeof(Vis)); -         inch[Root] =0; -          for(i =0; i < V; i++)//Mark each ring the         { -RET + =inch[i];//Record weight valueWuyi             intv =i; the              while(Vis[v]! = i && id[v] = =-1&& V! =root) -             { WuVIS[V] =i; -v =Pre[v]; About             } $             if(v! = root && id[v] = =-1) -             { -                  for(intU = pre[v]; U! = V; U =Pre[u]) -Id[u] = cnt;//Mark Node U is the first ring AID[V] = cnt++; +             } the         } -         if(CNT = =0) $              Break;//No ring break the          for(i =0; i < V; i++) the             if(Id[i] = =-1) theId[i] = cnt++; the             //3. Create a new zoom point, re-mark -              for(i =0; i < E; i++) in             { the                 intU =edge[i].u; the                 intv =edge[i].v; AboutEDGE[I].U =Id[u]; theEDGE[I].V =Id[v]; the                 if(Id[u]! =Id[v]) theEDGE[I].W-=inch[v]; +             } -V =CNT; theRoot =Id[root];Bayi     } the     returnret; the } - intMain () - { the     inti; the      while(SCANF ("%d%d", &n, &m)! =EOF) the     { theType sum =0; -          for(i =0; I < m; i++) the         { thescanf"%d%d%i64d", &edge[i].u, &AMP;EDGE[I].V, &EDGE[I].W); theedge[i].u++; edge[i].v++;94Sum + =EDGE[I].W; the         } theSum + +; the          for(i = m; i < M + N; i++)//Add Super Node 0, node 0 to the rest of the Benquan the same (the edge of the title is greater than the original image of the total edge weight)98         { AboutEDGE[I].U =0; -EDGE[I].V = I-m +1;101EDGE[I].W =sum;102         }103Type ans = directed_mst (0, n +1, M +n);104         //n+1 is the sum of points, M+n is the total number of edges the         //ans represents the total weight of the smallest tree diagram rooted in Super node 0,106         //The ans minus sum, if the difference is less than sum, indicating that the out of node 0 is only 1, indicating that the original is connected graph107         //If the difference is >=sum, then the exit of node 0 is more than 1, indicating that the original is not a connected graph108         if(ans = =-1|| Ans-sum >=sum)109Puts"Impossible"); the         Else111printf"%i64d%d\n", Ans-sum, pos-m); thePuts"");113     } the     return 0; the}

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No root minimum tree chart template