Submission #1032216

#	Time	Username	Problem	Language	Result	Execution time	Memory
1032216		shmax	Arranging Shoes (IOI19_shoes)	C++17	45 / 100	44 ms	6744 KiB

shoes

#include "shoes.h"
#include <bits/stdc++.h>

using namespace std;
using i32 = int;
#define int long long
#define len(x) (int)(x.size())
#define inf 1000'000'000'000'000'000LL
#define all(x) x.begin(), x.end()
#define low_bit(x) (x & (-x))

template<typename T>
using vec = vector<T>;

template<typename T>
struct fenvik {
private:
    vec<T> fen;

    T _get(int x) {
        T res = 0;
        for (int i = x; i > 0; i -= low_bit(i)) {
            res += fen[i];
        }
        return res;
    }

    void _add(int x, T val) {
        for (int i = x; i < len(fen); i += low_bit(i)) {
            fen[i] += val;
        }
    }

public:
    void init(int x) {
        fen.clear();
        fen.resize(x + 1);
    }

    void inc(int i, T x) {
        i++;
        _add(i, x);
    }

    T get(int l, int r) {
        if (l == 0) return _get(r + 1);
        return _get(r + 1) - _get(l);
    }

    T get(int i) {
        return get(i, i);
    }

    void set(int i, T x) {
        inc(i, x - get(i));
    }
};


int count_swaps(vec<i32> s) {
    int n = len(s);
    deque<int> p1, p0;
    for (int i = 0; i < n; i++) {
        if (s[i] > 0) p1.push_back(i);
        else p0.push_back(i);
    }

    fenvik<int> exist;
    exist.init(n);
    for (int i = 0; i < n; i++) {
        exist.set(i, 1);
    }
    int last = 1;
    int ans = 0;
    for (int i = 0; i < n; i++) {
        if (exist.get(i, i) == 0) continue;
        if (s[i] == -last) {
            last *= -1;
            if (s[i] == 1) {
                p1.pop_front();
            }
            if (s[i] == -1) {
                p0.pop_front();
            }
            continue;
        }
        if (last == 1) {
            int p = p0.front();
            p0.pop_front();
            exist.set(p, 0);
            ans += exist.get(i, p);
        } else {
            int p = p1.front();
            p1.pop_front();
            exist.set(p, 0);
            ans += exist.get(i, p);
        }
        i--;
        last *= -1;

    }
    return ans;

}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 20 / 20
• Subtask 4: 15 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15