Cod sursa(job #1547657)

Utilizator spatarelDan-Constantin Spatarel spatarel Data 9 decembrie 2015 18:38:08
Problema Range minimum query Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.96 kb
#include <cstdio>
#include <algorithm>

using std :: min;

const int maxN = 100000;

int v[maxN];
int rmq[20][maxN];
int Log[1 + maxN];

int rmQuery(int x, int y) {
  int l = y - x + 1;
  int step = Log[l];
  return min(rmq[step][x], rmq[step][y - (1 << step) + 1]);
}

void rmqCompute(int v[], int N) {
  for(int i = 0; i < N; ++ i)
    rmq[0][i] = v[i];
  for(int i = 1; (1 << i) <= N; ++ i)
    Log[(1 << i)] = 1;
  for(int i = 1; i <= N; ++ i)
    Log[i] += Log[i - 1];

  int p = 2;
  for(int step = 1; p <= N; ++ step, p <<= 1) {
    int put = p >> 1;
    for(int i = 0; i + put < N; ++ i)
      rmq[step][i] = min(rmq[step - 1][i], rmq[step - 1][i + put]);
  }
}

int main() {
  freopen("rmq.in", "r", stdin);
  freopen("rmq.out", "w", stdout);
  int N, T;
  scanf("%d %d", &N, &T);
  for(int i = 0; i < N; ++ i)
    scanf("%d", &v[i]);

  rmqCompute(v, N);

  int x, y;
  while(T --) {
    scanf("%d %d", &x, &y);
    printf("%d\n", rmQuery(x - 1, y - 1));
  }
  return 0;
}