Submission #298803

#	Time	Username	Problem	Language	Result	Execution time	Memory
298803		square1001	Arranging Shoes (IOI19_shoes)	C++14	30 / 100	59 ms	3064 KiB

shoes

#include "shoes.h"
#include <vector>
#include <algorithm>
using namespace std;
const int inf = 1012345678;
int count_inversions(int n, vector<int> a, vector<int> b) {
	vector<int> aprecnt(n);
	for(int i = 0; i < n; ++i) {
		for(int j = 0; j < i; ++j) {
			if(a[j] == a[i]) ++aprecnt[i];
		}
	}
	vector<int> perm(n);
	for(int i = 0; i < n; ++i) {
		int bprecnt = 0;
		for(int j = 0; j < i; ++j) {
			if(b[j] == b[i]) ++bprecnt;
		}
		for(int j = 0; j < n; ++j) {
			if(a[j] == b[i] && aprecnt[j] == bprecnt) {
				perm[i] = j;
			}
		}
	}
	int ans = 0;
	for(int i = 0; i < n; ++i) {
		for(int j = i + 1; j < n; ++j) {
			if(perm[i] > perm[j]) {
				++ans;
			}
		}
	}
	return ans;
}
long long count_swaps(std::vector<int> s) {
	int N = s.size() / 2;
	if(N <= 8) {
		// subtask 1, 2
		vector<int> sizes;
		for(int i = 0; i < 2 * N; ++i) {
			if(s[i] > 0) {
				sizes.push_back(s[i]);
			}
		}
		vector<int> perm(N);
		for(int i = 0; i < N; ++i) perm[i] = i;
		int ans = inf;
		do {
			vector<int> seq(2 * N);
			for(int i = 0; i < N; ++i) {
				seq[i * 2] = -sizes[perm[i]];
				seq[i * 2 + 1] = sizes[perm[i]];
			}
			int res = count_inversions(2 * N, seq, s);
			ans = min(ans, res);
		} while(next_permutation(perm.begin(), perm.end()));
		return ans;
	}
	return -1;
}

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