Submission #597986

#	Time	Username	Problem	Language	Result	Execution time	Memory
597986		Johann	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	252 ms	14840 KiB

shoes

#include "bits/stdc++.h"
using namespace std;

typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;
#define sz(x) (int) (x).size()

bool active[200200] = { false };

struct segtree {
    vi arr;
    int size;
    segtree(int _size) {
        size = 1;
        while (size < _size) size *= 2;
        arr.assign(2 * size, 0);
        for (int i = 0; i < _size; ++i) {
            arr[i + size] = i;
        }
    }
    void addOne(int l, int r, int x, int lx, int rx) {
        if (l <= lx && rx <= r) { arr[x] += 1; return; }
        if (r <= lx || rx <= l) { return; }
        int m = (lx + rx) / 2;
        addOne(l, r, 2 * x, lx, m);
        addOne(l, r, 2*x+1, m, rx);
    }
    void addOne(int i) {
        addOne(0, i, 1, 0, size);
    }
    int query(int i, int x, int lx, int rx) {
        if (rx - lx == 1) return arr[x];
        int m = (lx + rx) / 2;
        if (i < m) return query(i, 2 * x, lx, m) + arr[x];
        else return query(i, 2 * x + 1, m, rx) + arr[x];
    }
    int query(int i) {
        return query(i, 1, 0, size);
    }
};

ll count_swaps(vi S) {
    int n = sz(S) / 2;
    ll ans = 0;

    segtree seg(2 * n);
    set<pii> shoes;
    for (int i = 0; i < 2 * n; ++i) shoes.insert({ S[i], i });
    for (int i = 0; i < 2 * n; ++i) {
        if (active[i]) continue;
        active[i] = true;
        int pi = seg.query(i);
        int vi = S[i];
        auto it = shoes.lower_bound({ -vi, 0 });
        int j = it->second;
        active[j] = true;
        int pj = seg.query(j);
        shoes.erase(it);
        shoes.erase(shoes.lower_bound({vi, 0}));
        ans += (pj - pi);
        if (vi < 0) ans -= 1;
        seg.addOne(j);
    }
    return ans;
}

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