Submission #297248

#	Time	Username	Problem	Language	Result	Execution time	Memory
297248		A02	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	206 ms	33144 KiB

shoes

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

using namespace std;

void updateSegTree(vector<int> &segtree, int p, int a){

    int N = segtree.size() / 2;

    p += N;
    segtree[p] = a;
    p /= 2;

    while (p > 0){

        segtree[p] = segtree[2 * p] + segtree[2 * p + 1];
        p /= 2;

    }

}

long long querySegTree(vector<int> &segtree, int l, int r){

    int N = segtree.size() / 2;

    long long total = 0;

    for (l += N, r += N; l < r; l /= 2, r /= 2){

        if (l % 2 == 1){
            total += segtree[l++];
        }
        if (r % 2 == 1){
            total += segtree[--r];
        }
    }

    return total;
}

long long count_swaps(vector<int> s) {

	int N = s.size();

    long long total = 0;

    vector<int> segtree(2 * N, 0);

    for (int i = 0; i < N; i++){
        updateSegTree(segtree, i, 1);
    }

    vector<set<int> > positions (2 * N + 1, set<int> ());

    for (int i = 0; i < N; i++){
        positions[s[i] + N].insert(i);
    }

    for (int i = 0; i < N; i++){

        int current_value = querySegTree(segtree, i, i + 1);
        if (current_value == 1){

            int current_shoe = s[i];
            int desired_shoe = -current_shoe;

            int desired_shoe_location = *(positions[N + desired_shoe].begin());
            positions[N + desired_shoe].erase(positions[N + desired_shoe].begin());
            positions[N + current_shoe].erase(positions[N + current_shoe].begin());

            updateSegTree(segtree, i, 0);
            updateSegTree(segtree, desired_shoe_location, 0);

            if (desired_shoe < 0){
                total++;
            }

            total += querySegTree(segtree, i, desired_shoe_location);

        }

    }

	return total;
}

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