Submission #244811

#	Time	Username	Problem	Language	Result	Execution time	Memory
244811		crossing0ver	Arranging Shoes (IOI19_shoes)	C++17	0 / 100	5 ms	512 KiB

shoes

#include<bits/stdc++.h>
#define ll long long 
#include "shoes.h"
using namespace std;

ll count_swaps(vector<int> a) {
	int n = a.size();
	ll ans = 0;
	vector< vector<vector<int>> > v(2,vector< vector<int> >(n+1));
	for (int i = 0;i < n; i++) {
		if (a[i] < 0) v[1][-a[i]].push_back(i);
		else v[0][a[i]].push_back(i);
	}
	vector<int> vis(n,1);
	for (int i = 1; i <= n; i++)
	for (int t = 0; t < 2; t++)
		reverse(v[t][i].begin(),v[t][i].end());
	for (int i = 0; i < n;i++) {
		if (vis[i] == 0) continue;
		int x = a[i];
		int val = abs(x);
		int t = (x < 0 ? 0 : 1);
		int ps = v[t][x].back();
		vis[i] = 0;
		v[t][x].pop_back();
		v[!t][x].pop_back();
		for (int j = i + 1; j <= ps; j++)
			ans += vis[j];
		if (t == 0) ans++;
		vis[ps] = 0;
	}
	return ans;	
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:21:7: warning: unused variable 'val' [-Wunused-variable]
   int val = abs(x);
       ^~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15