Submission #147037

#	Time	Username	Problem	Language	Result	Execution time	Memory
147037		Denisov	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	119 ms	21236 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
#define ll long long
vector <int> t, used;
inline static int f (int i) {
    return i | (i + 1);
}
inline static int g (int i) {
    return i & (i + 1);
}
inline void upd (int i, int x) {
    for (; i < (int)t.size(); i = f(i)) t[i] += x;
}
inline int sum (int i) {
    int res = 0;
    for (; i >= 0; i = g(i) - 1) res += t[i];
    return res;
}
inline int sum (int l, int r) {
    return sum(r) - sum(l - 1);
}
vector<vector <int> > pos;
inline int get_pos (int x, int n) {
    if (pos[-x + n].empty()) {
        cout << "HOW";
        exit(0);
    }
    return pos[-x + n].back();
}
ll count_swaps(vector<int> a) {
    ll ans = 0; int n = (int)a.size();
    t.resize(n);
    pos.resize(n + n + 1);
    used.resize(n + n + 1);
    for (int i = 0; i < n; i++) {
        pos[a[i] + n].push_back(i);
    }
    for (auto &i : pos) reverse(i.begin(), i.end());
    for (int i = 0; i < n; i++) {
        if (used[a[i] + n] > 0) {
            --used[a[i] + n];
            continue;
        }
        int cur = i + sum(i), x = get_pos(a[i], n);
        int to = x + sum(x);
        ans += to - cur - 1 + bool(a[i] > 0);
        upd(i, 1);
        upd(x, -1);
        pos[a[i] + n].pop_back();
        pos[-a[i] + n].pop_back();
        ++used[-a[i] + n];
    }
    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