Submission #408812

#	Time	Username	Problem	Language	Result	Execution time	Memory
408812		dxz05	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	267 ms	276804 KiB

shoes

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

using namespace std;

typedef long long ll;

const int MAXN = 4e5 + 6e3;

int f[MAXN];

void add(int x, int y){
    x++;
    while (x < MAXN){
        f[x] += y;
        x += (-x & x);
    }
}

void add(int l, int r, int y){
    if (l > r) return;
    add(l, y);
    add(r + 1, -y);
}

int get(int x){
    x++;
    int sum = 0;
    while (x > 0){
        sum += f[x];
        x -= (-x & x);
    }
    return sum;
}

int get(int l, int r){
    return get(r) - get(l - 1);
}

int code(int val){
    return (val < 0 ? -val : val + 200000);
}

queue<int> q[MAXN];

long long count_swaps(vector<int> a) {
	int n = a.size();

	for (int i = 0; i < n; i++){
        q[code(a[i])].push(i);
	}

    ll ans = 0;

    for (int i = 0; i < n; i++){
        if (get(i, i)) continue;

        int x = code(a[i]), y = code(-a[i]);

        int pos1 = i, pos2 = q[y].front();
        ans += pos2 - pos1 - 1 + (a[i] > 0);
        ans -= get(pos1, pos2);

        add(pos1, 1);
        add(pos2, 1);

        q[x].pop();
        q[y].pop();
    }

	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