Cod sursa(job #2508205)

Utilizator tifui.alexandruTifui Ioan Alexandru tifui.alexandru Data 11 decembrie 2019 18:58:43
Problema Range minimum query Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.42 kb
#include <bits/stdc++.h>

using namespace std;

class RMQ{

    private:
        int** rmq;
        int* LOG2;
        int N;
        int *v;

    public:
        RMQ(int n, int *w){

            rmq = new int*[(int)log2(n) + 5]();
            LOG2 = new int[n + 5]();
            N = n;
            v = w;

            for(int i = 0; i < (int)log2(n) + 5; ++i)
                rmq[i] = new int[n + 5]();
        }

        void build(){

            rmq[0][1] = v[1];
            for(int i = 2; i <= N; ++i){

                LOG2[i] = LOG2[i >> 1] + 1;
                rmq[0][i] = v[i];
            }

            for(int j, i = 1; i <= LOG2[N]; ++i)
                for(j = 1; j + (1 << (i - 1)) <= N; ++j)
                    rmq[i][j] = min(rmq[i - 1][j], rmq[i - 1][j + (1 << (i - 1))]);
        }

        int query(int i, int j){

            int k = LOG2[j - i + 1];
            return min(rmq[k][i], rmq[k][j - (1 << k) + 1]);
        }
};

const int Nmax = 1e5 + 5;
int v[Nmax];

int main(){

    ios_base :: sync_with_stdio(false);
    cin.tie(nullptr);
    freopen("rmq.in", "r", stdin);
    freopen("rmq.out", "w", stdout);

    int n, m;
    cin >> n >> m;
    for(int i = 1; i <= n; ++i)
        cin >> v[i];

    RMQ T(n, v);
    T.build();

    while(m--){

        int x, y;
        cin >> x >> y;
        cout << T.query(x, y) << '\n';
    }

    return 0;
}