Cod sursa(job #3225717)

Utilizator ArcherraikoNedelcu Stefan Daniel Archerraiko Data 18 aprilie 2024 16:12:07
Problema Range minimum query Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.53 kb
#include <fstream>
using namespace std;
int a[10001];
int rmq[10001][18], LOG[10001];

//query in O(1), functioneaza doar pentru functii idempotente
int query1(int x, int y) {
    int k = LOG[y - x + 1];
    return min(rmq[x][k], rmq[y - (1 << k) + 1][k]);
}

//query in O(log(n)), merge si pe functii neidempotente
int query2(int x, int y) {
    int diff = y - x + 1;
    int st = x;
    int sol = 1e9;
    for (int i = 0; (1 << i) <= diff; i++) {
        if ((1 << i) & diff) {
            sol = min(sol, rmq[st][i]);
            st += (1 << i);
        }
    }
    return sol;
}

int main() {
    ifstream cin("rmq.in");
    ofstream cout("rmq.out");
    int n,m,x,y;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    for (int i = 2; i <= n; i++) {
        LOG[i] = LOG[i / 2] + 1;
    }
    for (int i = 1; i <= n; i++) {
        rmq[i][0] = a[i];
    }
    for (int j = 1; (1 << j) <= n; j++) {
        for (int i = 1; i + (1 << j) - 1 <= n; i++) {
            rmq[i][j] = min(rmq[i][j - 1], rmq[i + (1 << (j - 1))][j - 1]);
        }
    }
    for (int i = 1; i <= m; i++) {
        cin >> x >> y;
        cout << query1(x, y);
    }
    return 0;
}

// https://infoarena.ro/problema/rmq
// https://www.pbinfo.ro/probleme/1735/divquery
// https://www.pbinfo.ro/probleme/3860/consecutive1
// https://www.infoarena.ro/problema/stramosi
// https://www.infoarena.ro/problema/lca
// https://www.youtube.com/watch?v=0jWeUdxrGm4
// https://www.youtube.com/watch?v=oib-XsjFa-M