HDU 5441 Travel

Test instructions: A person who does not want to be in a bus or other time wants to travel, give N cities, m roads and Q inquiries

Test instructions thought reference: Portal

PS: Brute force n times minimum spanning tree must timeout, because the number of edges reached 10 of 5

1#include <cmath>2#include <cstring>3#include <cstdio>4#include <algorithm>5 using namespacestd;6 intn,m,q;7 Const intqq=20005;8 intPRE[QQ];9 intSUM[QQ];Ten intTAR[QQ]; One structEdge A { -     intu,v,w; -     BOOL operator< (Edge a)Const the     { -         returnw<A.W; -     } -}edge[qq*5]; + structQuery - { +     intMoney ; A     intorder; at     BOOL operator< (Query b)Const -     { -         returnmoney<b.money;//always forget to bring return -     } - }QUERY[QQ]; - intFindintx) in { -     if(X==pre[x])returnx; to     returnpre[x]=find (Pre[x]); + } - voidSlove () the { *      for(intI=1; i<=n;++i) { $pre[i]=i; Panax Notoginsengsum[i]=1;//initialize each of the connected blocks -     } the     intans=0; +     intj=0; A      for(intI=0; i<q;++i) { the          for(; J<m && edge[j].w<=query[i].money;++j) { +             intu,v; -u=edge[j].u;v=edge[j].v; $             intX=find (U);inty=Find (v); $             if(x==y)Continue; -Ans+=sum[x]*sum[y];//How many 22 combinations of cities will be added when connecting block X and connected block y to form a new connected block?  -Pre[y]=x;//The city here is a combination, not an orderly pair the                     //In other words, each element of the connected block X can form a new city with any element in the connected block y . -                         //So here is the number of elements connecting block x to multiply the elements of the connected block Y,WuyiSum[x]=sum[x]+sum[y];//two connected blocks connect to a connected block, update the number of elements of the connected block the         }                              -tar[query[i].order]=ans*2;//because it is ordered, so multiply by 2, Wu}//The corresponding order to fill in the value, -      for(intI=0; i<q;++i) Aboutprintf"%d\n", Tar[i]); $ } - intMain () - { -     intT;SCANF ("%d",&t); A      while(t--){ +scanf"%d%d%d",&n,&m,&q); the          for(intI=0; i<m;++i) -scanf"%d%d%d",&edge[i].u,&edge[i].v,&EDGE[I].W); $          for(intI=0; i<q;++i) { thescanf"%d",&Query[i].money); theQuery[i].order=i;//record labels to fill values with arrays the         } theSort (edge,edge+m); -Sort (query,query+q); in slove (); the     } the     return 0; About}

HDU 5441 Travel