Cod sursa(job #2084967)

Utilizator netfreeAndrei Muntean netfree Data 9 decembrie 2017 13:56:23
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.91 kb
#include <bits/stdc++.h>

using namespace std;

const int N_MAX = 100000 + 5;

int n, m, dp[N_MAX][30], a[N_MAX];

ifstream fin ("rmq.in");
ofstream fout("rmq.out");

void init() {
    for(int i = 1; i <= n; i++)
          dp[i][0] = i;

    for(int j = 1; (1 << j) <= n; j++)
          for(int i = 1; i + (1 << j) - 1 <= n; i++)
              if (a[dp[i][j - 1]] < a[dp[i + (1 << (j - 1))][j - 1]])
                  dp[i][j] = dp[i][j - 1];
              else
                  dp[i][j] = dp[i + (1 << (j - 1))][j - 1];
}

int query(int i, int j){
    int k = log2(j - i + 1);
    if(a[dp[i][k]] <= a[dp[j - (1 << k) + 1][k]])
        return dp[i][k];
    return dp[j - (1 << k) + 1][k];
}

int main () {
    fin >> n >> m;
    for(int i = 1; i<=n; ++i)
        fin >> a[i];
    init();
    while(m--){
        int aa, bb; fin >> aa >> bb;
        fout << a[query(aa, bb)] << "\n";
    }
}