Cod sursa(job #1938257)

Utilizator iulianrotaruRotaru Gheorghe-Iulian iulianrotaru Data 24 martie 2017 18:44:15
Problema Radiatie Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 3.17 kb
#include <bits/stdc++.h>
using namespace std;
class InputReader {
    public:
        InputReader() {}
        InputReader(const char *file_name) {
            input_file = fopen(file_name, "r");
            cursor = 0;
            fread(buffer, SIZE, 1, input_file);
        }
        inline InputReader &operator >>(int &n) {
            while((buffer[cursor] < '0' || buffer[cursor] > '9')&& buffer[cursor]!='-') {
                advance();
            }
            semn=1;
            if(buffer[cursor]=='-')
            {
                semn=-1;
                advance();
            }
            n = 0;
            while('0' <= buffer[cursor] && buffer[cursor] <= '9') {
                n = n * 10 + buffer[cursor] - '0';
                advance();
            }
            n*=semn;
            return *this;
        }
    private:
        FILE *input_file;
        static const int SIZE = 1 << 20;
        int cursor,semn;
        char buffer[SIZE];
        inline void advance() {
            ++ cursor;
            if(cursor == SIZE) {
                cursor = 0;
                fread(buffer, SIZE, 1, input_file);
            }
        }
}f("radiatie.in");
ofstream g("radiatie.out");
int n,m,k,i,x,y,nr,j,K,L[1<<14],P[1<<14],GR[1<<14],put[1<<16],rmq[17][1<<16],V[17][1<<16],T[17][1<<16];
bool viz[1<<14];
vector <pair <int,int> > G[1<<14];
struct pt
{
    int x,y,c;
}v[1<<15];
bool cmp(pt a,pt b)
{
    return a.c<b.c;
}
void dfs(int x,int level)
{
    for(int i=1;i<=14;++i)
    {
        T[i][x]=T[i-1][T[i-1][x]];
        V[i][x]=max(V[i-1][x],V[i-1][T[i-1][x]]);
    }
    viz[x]=1;
    L[x]=level;
    rmq[0][++nr]=x;
    P[x]=nr;
    for(int i=0;i<(int)G[x].size();++i)
        if(!viz[G[x][i].first])
    {
        V[0][G[x][i].first]=G[x][i].second;
        T[0][G[x][i].first]=x;
        dfs(G[x][i].first,level+1);
        rmq[0][++nr]=x;
    }
}
void build_rmq()
{
    put[1]=0;
    for(i=2;i<=nr;i++) put[i]=put[i/2]+1;
    for(i=1;(1<<i)<=nr;++i)
        for(j=1,k=1<<(i-1);j<=nr;++j)
            rmq[i][j]=(L[rmq[i-1][j]]<L[rmq[i-1][j+k]]?rmq[i-1][j]:rmq[i-1][j+k]);
}
int LCA(int x,int y)
{
    if(P[x]>P[y]) swap(x,y);
    int d=put[P[y]-P[x]];
    int nod=rmq[d][P[y]-(1<<d)+1];
    if(L[nod]>L[rmq[d][P[x]]]) nod=rmq[d][P[x]];
    return nod;
}
int query(int x,int y)
{
    if(x==y) return 0;
    int dist=L[y]-L[x],sol=0;
    for(int i=14;i>=0;--i)
        if(dist&(1<<i))
        {
            sol=max(sol,V[i][y]);
            y=T[i][y];
            dist-=(1<<i);
        }
    return sol;
}
int gr(int i)
{
    if(GR[i]!=i) GR[i]=gr(GR[i]);
    return GR[i];
}
int main()
{
    f>>n>>m>>K;
    for(i=1;i<=m;++i) f>>v[i].x>>v[i].y>>v[i].c;
    sort(v+1,v+m+1,cmp);
    for(i=1;i<=n;++i) GR[i]=i;
    for(i=1;i<=m;++i)
        if(gr(v[i].x)!=gr(v[i].y))
    {
        G[v[i].x].push_back(make_pair(v[i].y,v[i].c));
        G[v[i].y].push_back(make_pair(v[i].x,v[i].c));
        GR[gr(v[i].x)]=GR[v[i].y];
    }
    dfs(1,1);
    build_rmq();
    while(K--)
    {
        f>>x>>y;
        int rad=LCA(x,y);
        g<<max(query(rad,x),query(rad,y))<<'\n';
    }
    return 0;
}