POJ-2349 Arctic Network---The long edge of the MST

Topic Links:

https://vjudge.net/problem/POJ-2349

Main topic:

To establish a communication network between n nodes, where m nodes can be directly connected by satellite, and the remaining nodes are connected by line, to find out how long the maximum length of these lines will take

Ideas:

or the bare topic of MST, because there are m nodes can be connected by satellite, so after the MST, the longest m-1 edge can be connected with a satellite, just require the first m long edge, directly with the prim algorithm, save the length of each edge of MST, sorted directly after the output of the long edge.

1#include <iostream>2#include <cstdio>3#include <cstring>4#include <algorithm>5#include <cmath>6#include <queue>7#include <stack>8#include <map>9#include <Set>Ten#include <sstream> One using namespacestd; AtypedefLong Longll; -typedef pair<int,int>Pair; - Const intMAXN = 1e3 +Ten; the Const intINF =1<< -; - intdir[4][2] = {1,0,0,1,-1,0,0,-1}; - intT, N, M; - DoubleMAP[MAXN][MAXN];//Save Diagram + DoubleLOWCOST[MAXN], ANS[MAXN]; - intMST[MAXN], tot; + Pair A[MAXN]; A voidPrimintU//minimum spanning tree start at { -      for(inti =1; I <= N; i++)//Initialize two arrays -     { -Lowcost[i] =Map[u][i]; -Mst[i] =u; -     } inMst[u] =-1;//set to 1 to indicate that the MST has been added -      for(inti =1; I <= N; i++) to     { +         DoubleMinn =INF; -         intv =-1; the         //find the minimum value for the lowcost array that is not included in MST *          for(intj =1; J <= N; J + +) $         {Panax Notoginseng             if(Mst[j]! =-1&& Lowcost[j] <Minn) -             { thev =J; +Minn =Lowcost[j]; A             } the         } +         if(V! =-1)//V=-1 indicates that the smallest edge is not found, -{//v indicates the shortest point of the current distance to MST $             //printf ("%d%d%d\n", Mst[v], V, Lowcost[v]);//Output Path $ans[tot++] =Lowcost[v]; -MST[V] =-1; -              for(intj =1; J <= N; J + +)//update the shortest edge the             { -                 if(Mst[j]! =-1&& Lowcost[j] >Map[v][j])Wuyi                 { theLOWCOST[J] =Map[v][j]; -MST[J] =v; Wu                 } -             } About         } $     } -     //printf ("Weight of MST is%d\n", sum_mst); -Sort (ans, ans +tot); -printf"%.2f\n", Ans[n-m-1]);//outputs the side of the M-long A } + intMain () the { -CIN >>T; $      while(t--) the     { theCIN >> M >>N; the          for(inti =1; I <= N; i++) Cin >> A[i].first >>A[i].second; the          for(inti =1; I <= N; i++) -         { in              for(intj =1; J <= N; J + +) theMAP[I][J] = map[j][i] = sqrt ((a[i].first-a[j].first) * (A[i].first-a[j].first) + (a[i].second-a[j].second) * (A[I].S Econd-a[j].second)); the         } Abouttot =0; thePrim1); the     } the     return 0; +}

POJ-2349 Arctic Network---The long edge of the MST