Submission #1215516

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215516		mychecksedad	Sorting (IOI15_sorting)	C++20	100 / 100	234 ms	16744 KiB

sorting

#include "sorting.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
#define ff first
#define ss second
#define pii pair<int,int>
#define vi vector<int>
const int N = 1e6+100, M = 1e5+10, K = 52, MX = 30;


int findSwapPairs(int n, int S[], int m, int X[], int Y[], int P[], int Q[]) {
  int l = 0, r = m, ans = m;
  while(l <= r){
  	int mid = l+r>>1;
  	vector<pii> SW;

  	vector<int> v, pos_val(n), pos_plate(n), plate(n), val(n);
  	for(int i = 1; i <= n; ++i) v.pb(i-1);

  	for(int i = 0; i < n; ++i) val[i] = S[i], pos_val[S[i]] = i;
  	for(int i = 0; i < mid; ++i){
  		swap(val[X[i]], val[Y[i]]);
  	}

  	for(int i = 0; i < n; ++i){
  		plate[pos_val[val[i]]] = i;
  	}
  	for(int i = 0; i < n; ++i) val[i] = S[i], pos_val[S[i]] = i;
  	for(int i = 0; i < n; ++i) pos_plate[plate[i]] = i;



  	// cerr << mid << " plate\n";
  	// for(int x: plate) cerr << x << ' ';
  	// cerr << '\n';
  	for(int i = 0; i < mid; ++i){
  		swap(val[X[i]], val[Y[i]]);
  		swap(pos_val[val[X[i]]], pos_val[val[Y[i]]]);
  		swap(plate[X[i]], plate[Y[i]]);
  		swap(pos_plate[plate[X[i]]], pos_plate[plate[Y[i]]]);

  		while(v.size() && pos_plate[v.back()] == pos_val[v.back()]){
  			v.pop_back();
  		}
  		if(v.empty()){
  			SW.pb({0, 0}); // no swap
  		}else{
  			int vall = v.back();
  			v.pop_back();
  			int x = pos_plate[vall];
  			int y = pos_val[vall];
  			SW.pb({x, y});
  			
	  		swap(val[x], val[y]);
	  		swap(pos_val[val[x]], pos_val[val[y]]);
	  		// swap(plate[x], plate[y]);
	  		// swap(pos_plate[plate[x]], pos_plate[plate[y]]);
  		}

  		// cerr << "after " << i << '\n';
  		// for(int x: val) cerr << x << ' '; cerr << '\n';
  		// for(int x: plate) cerr << x << ' '; cerr << '\n';
  		// 	cerr << '\n';
  	}


  	// cerr << mid << '\n';
  	// for(int x: plate) cerr << x << ' ';
  	// cerr << '\n';

  	bool ok = 1;
  	for(int i = 1; i < n; ++i) ok = ok & (val[i] > val[i - 1]);

  	if(ok){
  		ans = mid;
  		r = mid - 1;
  		for(int i = 0; i < mid; ++i) P[i] = SW[i].ff, Q[i] = SW[i].ss;
  	}else{
  		l = mid + 1;
  	}
  }
  return ans;
}

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 20 / 20
• Subtask 6: 26 / 26