Cod sursa(job #2772201)

Utilizator tibinyteCozma Tiberiu-Stefan tibinyte Data 31 august 2021 11:42:39
Problema Range minimum query Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 4.42 kb
#include<bits/stdc++.h>
#pragma warning (disable : 26451)
#pragma warning (disable : 4996)
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");
template<typename T> struct rmq {
    vector<T> v; int n;
    static const int b = 30;
    vector<int> mask, t;
    int op(int x, int y) {
        return v[x] < v[y] ? x : y;
    }
    int lsb(int x) {
        return x & -x;
    }
    int msb_index(int x) {
        return __builtin_clz(1) - __builtin_clz(x);
    }
    int small(int r, int size = b) {
        int dist_from_r = msb_index(mask[r] & ((1 << size) - 1));

        return r - dist_from_r;
    }
    rmq(const vector<T>& v_) : v(v_), n(v.size()), mask(n), t(n) {
        int curr_mask = 0;
        for (int i = 0; i < n; i++) {
            curr_mask = (curr_mask << 1) & ((1 << b) - 1);
            while (curr_mask > 0 and op(i, i - msb_index(lsb(curr_mask))) == i) {
                curr_mask ^= lsb(curr_mask);
            }           curr_mask |= 1;
            mask[i] = curr_mask;
        }
        for (int i = 0; i < n / b; i++) t[i] = small(b * i + b - 1);
        for (int j = 1; (1 << j) <= n / b; j++) for (int i = 0; i + (1 << j) <= n / b; i++)
            t[n / b * j + i] = op(t[n / b * (j - 1) + i], t[n / b * (j - 1) + i + (1 << (j - 1))]);
    }
    T query(int l, int r) {
        if (r - l + 1 <= b) return v[small(r, r - l + 1)];
        int ans = op(small(l + b - 1), small(r));
        int x = l / b + 1, y = r / b - 1;
        if (x <= y) {
            int j = msb_index(y - x + 1);
            ans = op(ans, op(t[n / b * j + x], t[n / b * j + y - (1 << j) + 1]));
        }
        return v[ans];
    }
};
int main() {
    int n;
    cin >> n;
    vector<int> a(n + 1);
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
    }
    rmq<int> mini(a);
    int q;
    cin >> q;
    while (q--) {
        int st, dr;
        cin >> st >> dr;
        cout << mini.query(st, dr) << '\n';
    }
}