Submission #143592

#	Time	Username	Problem	Language	Result	Execution time	Memory
143592		kdh9949	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	116 ms	24852 KiB

shoes

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

#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define ppb pop_back
#define all(x) x.begin(),x.end()
#define cppio ios_base::sync_with_stdio(0);cin.tie(0)

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int N = 200005;

vector<int> u[N], v[N], t[N];
vector<pii> w;
int a[N];

struct BIT{
	int d[N];
	void u(int x){ for(; x < N; x += x & -x) d[x]++; }
	int g(int x){ int r = 0; for(; x; x -= x & -x) r += d[x]; return r; }
	int g(int s, int e){ return g(e) - g(s - 1); }
} B;

ll count_swaps(vector<int> s) {
	int n = s.size() / 2;
	for(int i = 0; i < 2 * n; i++) (s[i] < 0 ? u : v)[abs(s[i])].pb(i);
	for(int i = 1; i <= n; i++) for(int j = 0; j < u[i].size(); j++) w.pb(pii(u[i][j], v[i][j]));
	sort(all(w), [](pii x, pii y){ return x.x + x.y < y.x + y.y; });
	for(int i = 0; i < n; i++){
		a[w[i].x] = 2 * i + 1;
		a[w[i].y] = 2 * i + 2;
	}
	ll r = 0;
	for(int i = 0; i < 2 * n; i++){
		r += B.g(a[i] + 1, 2 * n);
		B.u(a[i]);
	}
	return r;
}

Compilation message (stderr)

shoes.cpp: In function 'll count_swaps(std::vector<int>)':
shoes.cpp:33:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 1; i <= n; i++) for(int j = 0; j < u[i].size(); j++) w.pb(pii(u[i][j], v[i][j]));
                                             ~~^~~~~~~~~~~~~

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