Cod sursa(job #2936789)

Utilizator erixEric stoicescu erix Data 9 noiembrie 2022 15:17:55
Problema Range minimum query Scor 40
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.96 kb
#include <fstream>
using namespace std;
#define MAX 100002
ifstream cin("rmq.in");
ofstream cout("rmq.out");
int sp[MAX][20];
int lg[MAX];

void buildSparseTable(int arr[], int n)
{
    for (int i = 0; i < n; i++)
        sp[i][0] = arr[i];

    int k = lg[n];
    for (int j = 1; j <= k; j++) {
        for (int i = 0; (i + (1<<j))-1 < n; i++) {
            sp[i][j] = min(sp[i][j - 1], sp[i + (1<<(j-1)) ][j-1]);
        }
    }
}

int query(int i, int j)
{
    int len = j-i+1;
    int k = lg[j - i + 1];

    return min(sp[i][k], sp[i+len-(1<<k)][k]);
}

int main()
{
    int n,q;
    cin >> n >> q;
    int* a = new int[n];
    for(int i = 0;i<n;i++) cin >> a[i];
    for(int i=2; i<=MAX; i++)
        lg[i] = 1 + lg[i/2];

    buildSparseTable(a, n);
    int k = lg[n];
    int L,R;
    for(int i = 0;i<q;i++){
        cin >> L >> R;
        L--;
        R--;
        cout << query(min(L,R),max(L,R)) << endl;
    }
    return 0;
}