LeetCode 솔루션

[5/25] 354. Russian Doll Envelopes

mingki 쪽지보내기 메일보내기 자기소개 아이디로 검색 전체게시물 작성
작성일 2022.05.24 20:05

7,164 조회
1 댓글
0 추천
0 비추천
목록 게시글 쓰기

[LeetCode 시즌 3] 2022년 5월 25일 문제입니다.

https://leetcode.com/problems/russian-doll-envelopes/

354. Russian Doll Envelopes

Hard

317377Add to ListShare

You are given a 2D array of integers envelopes where envelopes[i] = [wi, hi] represents the width and the height of an envelope.

One envelope can fit into another if and only if both the width and height of one envelope are greater than the other envelope's width and height.

Return the maximum number of envelopes you can Russian doll (i.e., put one inside the other).

Note: You cannot rotate an envelope.

Example 1:

Input: envelopes = [[5,4],[6,4],[6,7],[2,3]]
Output: 3
Explanation: The maximum number of envelopes you can Russian doll is 3 ([2,3] => [5,4] => [6,7]).

Example 2:

Input: envelopes = [[1,1],[1,1],[1,1]]
Output: 1

Constraints:

1 <= envelopes.length <= 105
envelopes[i].length == 2
1 <= wi, hi <= 105

#LeetCode, #Google, #Tiktok, #Uber, #Amazon, #ByteDance, #Apple, #Microsoft, #Array, #Binary Search, #Dynamic Programming(DP), #Sorting

링크

https://leetcode.com/problems/russian-doll-envelopes/ 1631 회 연결

익명
작성일 2022.05.25 18:24

C++
Runtime: 547 ms, faster than 36.76% of C++ online submissions for Russian Doll Envelopes.
Memory Usage: 77.6 MB, less than 70.81% of C++ online submissions for Russian Doll Envelopes.

class Solution {
public:
    int maxEnvelopes(vector<vector<int>>& envelopes) {
        sort(envelopes.begin(), envelopes.end(), [](const vector<int> &a, const vector<int> &b) {
            return a[0] == b[0] ? a[1] > b[1] : a[0] < b[0];
        });
        
        vector<int> dp;
        
        for (auto &e : envelopes) {
            auto low = lower_bound(dp.begin(), dp.end(), e[1]);
            if (low == dp.end()) {
                dp.push_back(e[1]);
            }
            else if (e[1] < *low) {
                *low = e[1];
            }
        }
        return dp.size();
    }
};