Submission #1264200

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264200		gustavo_d	Sorting (IOI15_sorting)	C++17	0 / 100	1 ms	584 KiB

sorting

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

const int MAXN = 2e5;

int p[MAXN];

int findSwapPairs(int n, int P[], int m, int hisX[], int hisY[], int myX[], int myY[]) {
    int l = 0, r = m; int ans = 0;
	while (l <= r) {
		int mid = (l + r) / 2;
		for (int i=0; i<n; i++) p[i] = P[i];
		for (int i=0; i<mid; i++) swap(p[hisX[i]], p[hisY[i]]);

		vector<pair<int, int>> ops(mid, make_pair(0, 0));
		vector<bool> mark(n, false);
		int swaps = 0; bool check = true;
		for (int i=0; i<n; i++) {
			if (mark[i]) continue;
			vector<int> cycle;
			int j = i;
			// cerr << "cycle:";
			while (!mark[j]) {
				mark[j] = true;
				cycle.push_back(j);
				// cerr << j << ' ';
				j = p[j];
			}
			// cerr << '\n';
			for (j=0; j<(int)cycle.size()-1; j++) {
				if (swaps > mid) {
					check = false;
					break;
				}
				ops[swaps++] = {cycle[j], cycle[j+1]};
			}
		}

		// cerr << mid << ':' << check << endl;
		if (check) {
			r = mid-1;
			for (int op=0; op<mid; op++) {
				myX[op] = ops[op].first;
				myY[op] = ops[op].second;
			}
			ans = mid;
		} else l = mid+1;
	}
	return ans;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 12
• Subtask 3: 0 / 16
• Subtask 4: 0 / 18
• Subtask 5: 0 / 20
• Subtask 6: 0 / 26