Submission #302286

#	Time	Username	Problem	Language	Result	Execution time	Memory
302286		square1001	Sorting (IOI15_sorting)	C++14	20 / 100	1038 ms	384 KiB

sorting

#include "sorting.h"
#include <random>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
mt19937 mt(2009190008);
int rand_rng(int l, int r) {
	uniform_int_distribution<int> p(l, r - 1);
	return p(mt);
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
	fill(P, P + M, 0);
	fill(Q, Q + M, 0);
	for(int i = 0; i < M; ++i) {
		if(is_sorted(S, S + N)) {
			return i;
		}
		swap(S[X[i]], S[Y[i]]);
		if(is_sorted(S, S + N)) {
			return i + 1;
		}
		vector<int> col(N, -1);
		for(int j = 0; j < N; ++j) {
			if(col[j] != -1) continue;
			int pos = j;
			while(col[pos] == -1) {
				col[pos] = j;
				pos = S[pos];
			}
		}
		do {
			P[i] = rand_rng(0, N);
			Q[i] = rand_rng(0, N);
		} while(P[i] == Q[i] || col[P[i]] != col[Q[i]]);
		swap(S[P[i]], S[Q[i]]);
	}
	if(is_sorted(S, S + N)) {
		return M;
	}
	return -1;
}

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