Cod sursa(job #1940688)

Utilizator savigunFeleaga Dragos-George savigun Data 26 martie 2017 19:18:28
Problema Range minimum query Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 1.36 kb
#include <iostream>
#include <fstream>
using namespace std;

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

const int BUF_SIZE = 1 << 17;

int n, nq, ptr;
int m[18][100005], v[100005], lg[100005];
char buffer[BUF_SIZE];


void advance() {
    ptr++;
    if (ptr == BUF_SIZE) {
        in.read(buffer, BUF_SIZE);
    }
}

int next_int() {
    int nr = 0;
    while (!isdigit(buffer[ptr])) advance();
    while (isdigit(buffer[ptr])) {
        nr = nr * 10 + (buffer[ptr] - '0');
        advance();
    }

    return nr;
}

void read() {
    in.read(buffer, BUF_SIZE);
    n = next_int();
    nq = next_int();
    for (int i = 1; i <= n; ++i) m[0][i] = next_int();
}

void logs() {
    for (int i = 2; i <= n; ++i) {
        lg[i] = lg[i / 2] + 1;
    }
}

void preprocess_rmq() {
    logs();

    for (int j = 1; (1 << j) <= n; ++j) {
        int val = n - (1 << j) + 1;
        for (int i = 1; i <= val; ++i) {
            m[j][i] = min(m[j-1][i], m[j-1][i + (1 << (j-1))]);
        }
    }
}

inline int rmq(int i, int j) {
    return min(m[lg[j - i + 1]][i], m[lg[j - i + 1]][i + j - i + 1 - (1 << lg[j - i + 1])]);
}


int main() {

    read();
    preprocess_rmq();
    for (int q = 1, i, j; q <= nq; ++q) {
        i = next_int();
        j = next_int();
        out << rmq(i, j) << '\n';
    }

    return 0;
}