oj.uz

Submission #751611

# Submission time Handle Problem Language Result Execution time Memory
751611 2023-06-01T01:16:17 Z rxlfd314 Sequence (APIO23_sequence) C++17
0 / 100
 146 ms 31568 KB 
#include "sequence.h"
#include <bits/stdc++.h>
using namespace std;
using ari2 = array<int, 2>;

int sequence(int N, vector<int> A) {
	if (false && N <= 2000) {
		int ans = 0;
		for (int i = 0; i < N; i++) {
			map<int, int> cnt;
			multiset<ari2> stuff;
			cnt[A[i]]++;
			stuff.insert({A[i], -i});
			auto it = stuff.begin();
			for (int j = i+1; j < N; j++) {
				stuff.insert({A[j], -j});
				cnt[A[j]]++;
				if (ari2{A[j], -j} < *it && (j - i & 1)) {
					it--;
				} else if (ari2{A[j], -j} > *it && !(j - i & 1)) {
					it++;
				}
				ans = max(ans, cnt[(*it)[0]]);
			}
		}
		return ans;
	}
	
	int middle = max_element(A.begin(), A.end()) - A.begin();
	bool mountain = true;	
	for (int i = middle - 1; i >= 0 && mountain; i--) {
		mountain &= A[i] <= A[i+1];
	}
	for (int i = middle + 1; i < N && mountain; i++) {
		mountain &= A[i] <= A[i-1];
	}
	if (mountain) {
		vector<int> inds[N];
		for (int i = 0; i < N; i++) {
			inds[A[i]-1].push_back(i);
		}
		
		int ans = 0;
		for (int ii = 0; ii < N; ii++) {
			if (inds[ii].size() < 2) {
				ans = max(ans, (int)inds[ii].size());
				continue;
			}
			int l1 = inds[ii][0], r1 = -1, l2 = -1, r2 = inds[ii].back();
			for (int i = 1; i < inds[ii].size(); i++) {
				if (inds[ii][i-1]+1 < inds[ii][i]) {
					r1 = inds[ii][i-1];
					l2 = inds[ii][i];
					break;
				}
			}
			if (r1 < 0) {
				ans = max(ans, r2 - l1 + 1);
			} else {
				int gap = l2 - r1 - 1;
				if (gap > r1 - l1 + 1 + r2 - l2 + 1) {
					if (l1 + N - r2 - 1 >= gap - (r1 - l1 + 1 + r2 - l2 + 1)) {
						ans = max(ans, r1 - l1 + 1 + r2 - l2 + 1);
					}
				} else {
					ans = max(ans, r1 - l1 + 1 + r2 - l2 + 1);
				}
			}
		}
		
		return ans;
	}
}

Compilation message

sequence.cpp: In function 'int sequence(int, std::vector<int>)':
sequence.cpp:18:36: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   18 |     if (ari2{A[j], -j} < *it && (j - i & 1)) {
      |                                  ~~^~~
sequence.cpp:20:44: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   20 |     } else if (ari2{A[j], -j} > *it && !(j - i & 1)) {
      |                                          ~~^~~
sequence.cpp:50:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |    for (int i = 1; i < inds[ii].size(); i++) {
      |                    ~~^~~~~~~~~~~~~~~~~
sequence.cpp:73:1: warning: control reaches end of non-void function [-Wreturn-type]
   73 | }
      | ^

Subtask #1
0.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 80 ms 25804 KB Output is correct
3 Correct 80 ms 25868 KB Output is correct
4 Correct 50 ms 18036 KB Output is correct
5 Correct 89 ms 24908 KB Output is correct
6 Correct 77 ms 24904 KB Output is correct
7 Incorrect 46 ms 18396 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #4
0.0 / 12.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 212 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0.0 / 13.0

# Verdict Execution time Memory Grader output
1 Incorrect 146 ms 31568 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -