Problem Link : http://lightoj.com:81/volume/problem/1101
#include <bits/stdc++.h> #define pii pair <int,int> #define pll pair <long long,long long> #define sc scanf #define pf printf #define Pi 2*acos(0.0) #define ms(a,b) memset(a, b, sizeof(a)) #define pb(a) push_back(a) #define MP make_pair #define db double #define ll long long #define EPS 10E-10 #define ff first #define ss second #define sqr(x) (x)*(x) #define D(x) cout<<#x " = "<<(x)<<endl #define VI vector <int> #define DBG pf("Hi\n") #define MOD 1000000007 #define CIN ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0) #define SZ(a) (int)a.size() #define sf(a) scanf("%d",&a) #define sfl(a) scanf("%lld",&a) #define sff(a,b) scanf("%d %d",&a,&b) #define sffl(a,b) scanf("%lld %lld",&a,&b) #define sfff(a,b,c) scanf("%d %d %d",&a,&b,&c) #define sfffl(a,b,c) scanf("%lld %lld %lld",&a,&b,&c) #define stlloop(v) for(__typeof(v.begin()) it=v.begin();it!=v.end();it++) #define loop(i,n) for(int i=0;i<n;i++) #define loop1(i,n) for(int i=1;i<=n;i++) #define REP(i,a,b) for(int i=a;i<b;i++) #define RREP(i,a,b) for(int i=a;i>=b;i--) #define TEST_CASE(t) for(int z=1;z<=t;z++) #define PRINT_CASE printf("Case %d:\n",z) #define CASE_PRINT cout<<"Case "<<z<<": " #define all(a) a.begin(),a.end() #define intlim 2147483648 #define infinity (1<<28) #define ull unsigned long long #define gcd(a, b) __gcd(a, b) #define lcm(a, b) ((a)*((b)/gcd(a,b))) using namespace std; /*----------------------Graph Moves----------------*/ //const int fx[]={+1,-1,+0,+0}; //const int fy[]={+0,+0,+1,-1}; //const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1}; // Kings Move //const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1}; // Kings Move //const int fx[]={-2, -2, -1, -1, 1, 1, 2, 2}; // Knights Move //const int fy[]={-1, 1, -2, 2, -2, 2, -1, 1}; // Knights Move /*------------------------------------------------*/ /*-----------------------Bitmask------------------*/ //int Set(int N,int pos){return N=N | (1<<pos);} //int reset(int N,int pos){return N= N & ~(1<<pos);} //bool check(int N,int pos){return (bool)(N & (1<<pos));} /*------------------------------------------------*/ typedef pair<int,pii > piii; vector< piii > g1; vector<int>g[50005],cost[50005]; int n,m; int par[50004]; int find_par(int u) { return par[u]=(par[u]==u)?u:find_par(par[u]); } int dis[50005],level[50005]; void dfs(int u, int cnt, int from) { level[u]=cnt; par[u]=from; for(int i=0; i<SZ(g[u]); i++) { int v=g[u][i]; if(level[v]==-1) { dis[v]=cost[u][i]; dfs(v,cnt+1,u); } } } int sparse_par[50005][16]; int sparse_max[50005][16]; void build_table() { ms(sparse_par,-1); for(int i=1; i<=n; i++) sparse_par[i][0]=par[i],sparse_max[i][0]=dis[i]; for(int i=1; 1<<i <=n; i++) { for(int j=1; j<=n; j++) if(sparse_par[j][i-1]!=-1) { sparse_par[j][i]=sparse_par[sparse_par[j][i-1]][i-1]; sparse_max[j][i]=max(sparse_max[j][i-1],sparse_max[sparse_par[j][i-1]][i-1]); } } } int query(int p, int q) { int a=p,b=q; if(level[p]<level[q]) swap(p,q); int log=log2(level[p]); int ret=0; for(int i=log; i>=0; i--) { if(level[p]-(1<<i) >=level[q]) { ret=max(ret,sparse_max[p][i]); p=sparse_par[p][i]; } } if(p==q) return ret; for(int i=log; i>=0; i--) if(sparse_par[p][i]!=-1 && sparse_par[p][i]!=sparse_par[q][i]) { ret=max(ret,max(sparse_max[p][i],sparse_max[q][i])); p=sparse_par[p][i],q=sparse_par[q][i]; } ret=max(ret,max(dis[p],dis[q])); return ret; } int main() { freopen("in.txt","r",stdin); ///freopen("out.txt","w",stdout); int t; sf(t); TEST_CASE(t) { g1.clear(); sff(n,m); for(int i=0; i<m; i++) { int a,b,c; sfff(a,b,c); g1.pb(piii(c,pii(a,b))); } sort(all(g1)); // reverse(all(g1)); int cnt=0; for(int i=1; i<=n; i++) par[i]=i,g[i].clear(),cost[i].clear(); for(int i=0; i<SZ(g1) && cnt<n-1; i++) { int a=g1[i].ss.ff; int b=g1[i].ss.ss; int c=g1[i].ff; int u=find_par(a); int v=find_par(b); if(u!=v) { par[v]=u; g[a].pb(b); g[b].pb(a); cost[a].pb(g1[i].ff); cost[b].pb(g1[i].ff); cnt++; } } ms(level,-1); dis[1]=0; dfs(1,0,1); build_table(); int q; sf(q); PRINT_CASE; while(q--) { int a, b; sff(a,b); printf("%d\n",query(a,b)); } } return 0; }