Leetcode#841. Keys and Rooms
ProblemThere are n rooms labeled from 0 to n - 1 and all the rooms are locked except for room 0. Your goal is to visit all the rooms. However, you cannot enter a locked room without having its key.
When you visit a room, you may find a set of distinct keys in it. Each key has a number on it, denoting which room it unlocks, and you can take all of them with you to unlock the other rooms.
Given an array rooms where rooms[i] is the set of keys that you can obtain if you visited room i, return true ...
Leetcode#392. Is Subsequence
ProblemGiven two strings s and t, return true if s is a subsequence of t, or false otherwise.
A subsequence of a string is a new string that is formed from the original string by deleting some (can be none) of the characters without disturbing the relative positions of the remaining characters. (i.e., "ace" is a subsequence of "abcde" while "aec" is not).
Example 1:
123Input: s = "abc", t = "ahbgdc"Output: true
Example 2:
123Input: s = "axc ...
Leetcode#1493. Longest Subarray of 1's After Deleting One Element
ProblemGiven a binary array nums, you should delete one element from it.
Return the size of the longest non-empty subarray containing only 1‘s in the resulting array. Return 0 if there is no such subarray.
Example 1:
1234Input: nums = [1,1,0,1]Output: 3Explanation: After deleting the number in position 2, [1,1,1] contains 3 numbers with value of 1's.
Example 2:
1234Input: nums = [0,1,1,1,0,1,1,0,1]Output: 5Explanation: After deleting the number in position 4, [0,1,1,1,1,1,0,1] longest suba ...
Leetcode#1456. Maximum Number of Vowels in a Substring of Given Length
ProblemGiven a string s and an integer k, return the maximum number of vowel letters in any substring of s with length k.
Vowel letters in English are 'a', 'e', 'i', 'o', and 'u'.
Example 1:
1234Input: s = "abciiidef", k = 3Output: 3Explanation: The substring "iii" contains 3 vowel letters.
Example 2:
1234Input: s = "aeiou", k = 2Output: 2Explanation: Any substring of length 2 contains 2 vowels.
Example 3:
1234Input: s = &qu ...
Leetcode#643. Maximum Average Subarray I
ProblemYou are given an integer array nums consisting of n elements, and an integer k.
Find a contiguous subarray whose length is equal to k that has the maximum average value and return this value. Any answer with a calculation error less than 10-5 will be accepted.
Example 1:
1234Input: nums = [1,12,-5,-6,50,3], k = 4Output: 12.75000Explanation: Maximum average is (12 - 5 - 6 + 50) / 4 = 51 / 4 = 12.75
Example 2:
123Input: nums = [5], k = 1Output: 5.00000
Constraints:
n == nums.length
1 < ...
Leetcode#283. Move Zeroes
ProblemGiven an integer array nums, move all 0‘s to the end of it while maintaining the relative order of the non-zero elements.
Note that you must do this in-place without making a copy of the array.
Example 1:
123Input: nums = [0,1,0,3,12]Output: [1,3,12,0,0]
Example 2:
123Input: nums = [0]Output: [0]
Constraints:
1 <= nums.length <= 10^4
2^31 <= nums[i] <= 2^31 - 1
Follow up:
Could you minimize the total number of operations done?
Solve123456789101112class Solution: def mov ...
Leetcode#1768. Merge Strings Alternately
ProblemYou are given two strings word1 and word2. Merge the strings by adding letters in alternating order, starting with word1. If a string is longer than the other, append the additional letters onto the end of the merged string.
Return the merged string.
Example 1:
1234567Input: word1 = "abc", word2 = "pqr"Output: "apbqcr"Explanation: The merged string will be merged as so:word1: a b cword2: p q rmerged: a p b q c r
Example 2:
1234567Input: word1 = & ...
Leetcode#435. Non-overlapping Intervals
ProblemGiven an array of intervals intervals where intervals[i] = [starti, endi], return the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.
Example 1:
1234Input: intervals = [[1,2],[2,3],[3,4],[1,3]]Output: 1Explanation: [1,3] can be removed and the rest of the intervals are non-overlapping.
Example 2:
1234Input: intervals = [[1,2],[1,2],[1,2]]Output: 2Explanation: You need to remove two [1,2] to make the rest of the intervals non-overlapping.
...
Leetcode#33. Search in Rotated Sorted Array
ProblemThere is an integer array nums sorted in ascending order (with distinct values).
Prior to being passed to your function, nums is possibly rotated at an unknown pivot index k (1 <= k < nums.length) such that the resulting array is [nums[k], nums[k+1], ..., nums[n-1], nums[0], nums[1], ..., nums[k-1]] (0-indexed). For example, [0,1,2,4,5,6,7] might be rotated at pivot index 3 and become [4,5,6,7,0,1,2].
Given the array nums after the possible rotation and an integer target, return the ...
Leetcode#1. Two Sum
ProblemGiven an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
You may assume that each input would have exactly one solution, and you may not use the same element twice.
You can return the answer in any order.
Example 1:
1234Input: nums = [2,7,11,15], target = 9Output: [0,1]Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].
Example 2:
123Input: nums = [3,2,4], target = 6Output: [1,2]
Example 3:
123Input: nums = [3,3 ...