Submission #677089

#	Time	Username	Problem	Language	Result	Execution time	Memory
677089		penguin133	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	140 ms	34196 KiB

shoes

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

//#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif

set<int> L[200005], R[200005];
long long vis[200005], ft[200005], n;

void upd(int l, int r, int v){
	r++;r++;
	l++;
	for(;l<=n;l+=(l & -l))ft[l] += v;
	for(;r<=n;r+=(r & -r))ft[r] -= v;
}

long long query(int p){
	p++;
	long long sum = 0;
	for(;p;p-=(p & -p))sum += ft[p];
	return sum;
}

long long count_swaps(std::vector<int> s) {
	n = (int)s.size();
	for(int i=0;i<n;i++){
		if(s[i] < 0)L[-s[i]].insert(i);
		else R[s[i]].insert(i);
	}
	for(int i=0;i<n;i++)upd(i, i, i);
	long long ans = 0;
	int cnt = 0;
	for(int i=0;i<n;i++){
		if(vis[i])continue;
		if(s[i] < 0){
			L[-s[i]].erase(L[-s[i]].begin());
			ans += max(0ll, query(*R[-s[i]].begin()) - query(i) - 1);
			vis[*R[-s[i]].begin()] = 1;
			upd(i+1, *R[-s[i]].begin(), 1);
			R[-s[i]].erase(R[-s[i]].begin());
		}
		else{
			ans++;
			R[s[i]].erase(R[s[i]].begin());
			ans += max(0ll, query(*L[s[i]].begin()) - query(i) - 1);
			vis[*L[s[i]].begin()] = 1;
			upd(i+1, *L[s[i]].begin(), 1);
			L[s[i]].erase(L[s[i]].begin());
		}
	}
	
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:39:6: warning: unused variable 'cnt' [-Wunused-variable]
   39 |  int cnt = 0;
      |      ^~~

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