Submission #258753

#	Time	Username	Problem	Language	Result	Execution time	Memory
258753		atoiz	Swap (BOI16_swap)	C++14	100 / 100	60 ms	5264 KiB

swap

#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>

using namespace std;

const int MAXN = 200007;
int N, A[MAXN * 2], B[MAXN];

int getMin(int i)
{
	if (B[i] == 0) return A[i];
	int ans;
	if ((i & 1)) {
		if (B[i ^ 1] == 1) ans = A[i ^ 1];
		else if (B[i ^ 1] == -1) ans = min(A[i ^ 1], getMin(i >> 1));
		else ans = getMin(i >> 1);
	} else {
		ans = getMin(i >> 1);
	}

	if (B[i] == -1) ans = min(ans, A[i]);
	return ans;
}

void retrieve(int i, int val)
{
	if (B[i] == 0) {
		assert(A[i] == val);
		return;
	}

	if (A[i] == val) {
		assert(B[i] == -1);
		B[i] = 0;
		return;
	}
	B[i] = 1;

	if ((i & 1)) {
		if (B[i ^ 1] == 1) assert(A[i ^ 1] == val);
		else if (B[i ^ 1] == -1) {
			B[i ^ 1] = (A[i ^ 1] == val);
			if (!B[i ^ 1]) retrieve(i >> 1, val);
		}
		else retrieve(i >> 1, val);
	} else retrieve(i >> 1, val);
}

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> N;
	for (int i = 1; i <= N; ++i) cin >> A[i];
	for (int i = N + 1; i <= 2 * N + 1; ++i) A[i] = MAXN;
	for (int i = 1; i <= N; ++i) {
		int cur = getMin(i);
		int minVal = min(cur, min(A[i << 1], A[i << 1 | 1]));
		if (cur == minVal) retrieve(i, cur);
		else if (A[i << 1] == minVal) {
			B[i << 1] = 1;
		} else {
			B[i << 1] = -1, B[i << 1 | 1] = 1;
		}
	}

	for (int i = 2; i <= N; ++i) if (B[i]) swap(A[i >> 1], A[i]);
	for (int i = 1; i <= N; ++i) cout << A[i] << ' '; cout << endl;
}

Compilation message (stderr)

swap.cpp: In function 'int main()':
swap.cpp:69:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for (int i = 1; i <= N; ++i) cout << A[i] << ' '; cout << endl;
  ^~~
swap.cpp:69:52: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  for (int i = 1; i <= N; ++i) cout << A[i] << ' '; cout << endl;
                                                    ^~~~

• Subtask 1: 10 / 10
• Subtask 2: 11 / 11
• Subtask 3: 27 / 27
• Subtask 4: 20 / 20
• Subtask 5: 32 / 32