Cod sursa(job #3151719)

Utilizator alexdumitruAlexandru Dumitru alexdumitru Data 22 septembrie 2023 17:31:32
Problema Range minimum query Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 3.34 kb
#include <fstream>
#pragma GCC optimize("O2")
#pragma GCC optimize("unroll-loops")
using namespace std;

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};

class OutParser {
private:
    FILE *fout;
    char *buff;
    int sp;

    void write_ch(char ch) {
        if (sp == 50000) {
            fwrite(buff, 1, 50000, fout);
            sp = 0;
            buff[sp++] = ch;
        } else {
            buff[sp++] = ch;
        }
    }


public:
    OutParser(const char* name) {
        fout = fopen(name, "w");
        buff = new char[50000]();
        sp = 0;
    }
    ~OutParser() {
        fwrite(buff, 1, sp, fout);
        fclose(fout);
    }

    OutParser& operator << (int vu32) {
        if (vu32 <= 9) {
            write_ch(vu32 + '0');
        } else {
            (*this) << (vu32 / 10);
            write_ch(vu32 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (long long vu64) {
        if (vu64 <= 9) {
            write_ch(vu64 + '0');
        } else {
            (*this) << (vu64 / 10);
            write_ch(vu64 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (char ch) {
        write_ch(ch);
        return *this;
    }
    OutParser& operator << (const char *ch) {
        while (*ch) {
            write_ch(*ch);
            ++ch;
        }
        return *this;
    }
};

InParser fin("rmq.in");
OutParser fout("rmq.out");

const int NMAX = 1e5;
const int VMAX = 1e5;

int n, q;
int a[NMAX + 1], aib1[NMAX + 1], aib2[NMAX + 1];

int x, y;

int main() {
    fin >> n >> q;
    for(int i = 1; i <= n; i++)
        aib1[i] = aib2[i] = VMAX;
    for(int i = 1; i <= n; i++){
        fin >> a[i];
        if(aib1[i] > a[i])
            aib1[i] = a[i];
        int next = i + (i & (-i));
        if(next <= n && aib1[next] > aib1[i])
            aib1[next] = aib1[i];
    }
    for(int i = n; i > 0; i--){
        if(aib2[i] > a[i])
            aib2[i] = a[i];
        int prev = i - (i & (-i));
        if(aib2[prev] > aib2[i])
            aib2[prev] = aib2[i];
    }
    while(q--){
        fin >> x >> y;
        int res = VMAX;
        int i = x;
        for(; i + (i & (-i)) <= y; i += (i & (-i)))
            if(res > aib2[i])
                res = aib2[i];
        if(res > a[i])
            res = a[i];
        for(; y - (y & (-y)) >= x; y -= (y & (-y)))
            if(res > aib1[y])
                res = aib1[y];
        fout << res << '\n';
    }
}