Submission #260383

#	Time	Username	Problem	Language	Result	Execution time	Memory
260383		terencehill	Arranging Shoes (IOI19_shoes)	C++14	10 / 100	1 ms	256 KiB

shoes

#include <bits/stdc++.h>
#define all(X) (X).begin(),(X).end()
#define rall(X) (X).rbegin(),(X).rend()
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define ff first
#define ss second
#define P 1000000007
#define in(x, a, b) (a <= x && x < b)

using namespace std;
using ll = long long;
typedef pair<int, int> ii;
typedef vector<ii> vii; 
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
const ll inf = 1000000001, INF = (ll)1e18 + 1;

void upd(vi &t, int pos, int val) {
	for(int i = pos + 1; i <= t.size(); i += (i&-i)) {
		t[i - 1] += val;
	}
}

int get(vi &t, int pos) {
	int sum = 0;
	for(int i = pos + 1; i > 0; i -= (i&-i)) {
		sum += t[i - 1];
	}
	
	return sum;
}

ll count_swaps(vi a) {
	int n = a.size();
	
	vi t(n, 0);
	for(int i = 0; i < n; i++) upd(t, i, 1);
	
	vi nxt(n);
	vvi u(n / 2 + 10, vi(2, -1));
	for(int i = n - 1; i >= 0; i--) {
		nxt[i] = u[abs(a[i])][(a[i] < 0 ? 0 : 1)];
		u[abs(a[i])][(a[i] < 0 ? 1 : 0)] = i;
	}
	
	ll ans = 0;
	for(int i = 0; i < n; i++) {
		if(nxt[i] == -1 || !(get(t, i) - get(t, i - 1))) continue;
		if(a[i] < 0) ans += get(t, nxt[i]) - get(t, i) - 1;
		else ans += get(t, nxt[i]) - get(t, i);
		upd(t, nxt[i], -1);
	}
	
	return ans;
}

//int main(){
//	ios_base::sync_with_stdio(false);
//	int n;
//	cin >> n;
//	
//	vi a(n);
//	for(int i = 0; i < n; i++) cin >> a[i];
//    
//    cout << count_swaps(a) << endl;
//	
//	return 0;
//}

Compilation message (stderr)

shoes.cpp: In function 'void upd(vi&, int, int)':
shoes.cpp:23:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = pos + 1; i <= t.size(); i += (i&-i)) {
                       ~~^~~~~~~~~~~

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