Submission #1067864

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067864		becaido	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	158 ms	140628 KiB

shoes

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifndef WAIMAI
#include "shoes.h"
#else
#include "grader.cpp"
#endif

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof...(u) ? ", " : ""), dout(u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

const int SIZE = 2e5 + 5;

int n;
ll ans;
deque<int> p[SIZE];
int a[SIZE], to[SIZE];

int bit[SIZE];
void upd(int pos, int x) {
    for (; pos <= 2 * n; pos += pos & -pos) bit[pos] += x;
}
int que(int pos) {
    int re = 0;
    for (; pos; pos -= pos & -pos) re += bit[pos];
    return re;
}
int que(int l, int r) {
    return que(r) - que(l - 1);
}

ll count_swaps(vector<int> s) {
    n = s.size() / 2;
    ans = 0;
    fill(bit + 1, bit + 2 * n + 1, 0);
    FOR (i, 1, 2 * n) {
        a[i] = s[i - 1];
        p[i].clear();
        to[i] = 0;
    }
    FOR (i, 1, 2 * n) {
        int x = a[i], y = abs(x);
        if (p[y].size() == 0 || a[p[y][0]] != -x) p[y].pb(i);
        else {
            to[p[y][0]] = i;
            p[y].pop_front();
        }
        upd(i, 1);
    }
    FOR (i, 1, 2 * n) if (to[i]) {
        ans += que(i + 1, to[i] - 1);
        if (a[i] > 0) ans++;
        upd(i, -1);
        upd(to[i], -1);
    }
    return ans;
}

/*
in1
2
2 1 -1 -2
out1
4

in2
3
-2 2 2 -2 -2 2
out2
1
*/

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