Cod sursa(job #2828347)

Utilizator SeracovanuEdwardSeracovanu Edward SeracovanuEdward Data 7 ianuarie 2022 09:23:57
Problema Stramosi Scor 0
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.14 kb
#include <bits/stdc++.h>
#define dim 250005
#define logg 18
using namespace std;
class prs{
private:
    FILE *fin;
    char *buff;
    int sp;
    char read_ch(){
    ++sp;
    if(sp==4096){
        sp=0;
        fread(buff,1,4096,fin);
    }
    return buff[sp];
    }
public:
    prs(const char *name){
    fin=fopen(name,"r");
    buff=new char [4096]();
    sp=4095;
    }
    prs& operator >> (int &n){
    char c;
    while(!isdigit(c=read_ch()));
    n=c-'0';
    while(isdigit(c=read_ch()))
        n=n*10+c-'0';
    return *this;
    }
};
int n,m;
vector <vector<int>> dp(dim,vector<int>(logg));
inline int query(int a,int b){
int curr=b;
int ans=a;
for(int i=logg-1;i>=0;--i)
    if((1<<i)<=curr){
    curr-=(1<<i);
    ans=dp[a][i];
    }
return ans;
}
int main()
{
    prs fin("stramosi.in");
    freopen("stramosi.out","w",stdout);
    fin>>n>>m;
    for(int i=1;i<=n;++i)
        fin>>dp[i][0];
    for(int j=1;(1<<j)<=n;++j)
        for(int i=1;i<=n;++i)
            dp[i][j]=dp[dp[i][j-1]][j-1];
    for(int i=1,x,y;i<=m;++i){
        fin>>x>>y;
        printf("%d\n",query(x-1,y-1));
    }
}