Lunski's Clutter

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Symbols count in article: 940 Reading time ≈ 1 mins.

There are a row of n houses, each house can be painted with one of the three colors: red, blue or green. The cost of painting each house with a certain color is different. You have to paint all the houses such that no two adjacent houses have the same color.

The cost of painting each house with a certain color is represented by a n x 3 cost matrix. For example, costs[0][0] is the cost of painting house 0 with color red; costs[1][2] is the cost of painting house 1 with color green, and so on… Find the minimum cost to paint all houses.

Note:
All costs are positive integers.

Example

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Input: [[17,2,17],[16,16,5],[14,3,19]]
Output: 10
Explanation: Paint house 0 into blue, paint house 1 into green, paint house 2 into blue. 
             Minimum cost: 2 + 5 + 3 = 10.
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Symbols count in article: 983 Reading time ≈ 1 mins.

Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to find the number of connected components in an undirected graph.

Example 1

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Input: n = 5 and edges = [[0, 1], [1, 2], [3, 4]]

     0          3
     |          |
     1 --- 2    4 

Output: 2

Example 2

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Input: n = 5 and edges = [[0, 1], [1, 2], [2, 3], [3, 4]]

     0           4
     |           |
     1 --- 2 --- 3

Output:  1
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Symbols count in article: 1.2k Reading time ≈ 1 mins.

Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.

Follow up: Could you implement a solution using only O(1) extra space complexity and O(n) runtime complexity?

Example 1:

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Input: nums = [3,0,1]
Output: 2
Explanation: n = 3 since there are 3 numbers, so all numbers are in the range [0,3]. 2 is the missing number in the range since it does not appear in nums.

Example 2:

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Input: nums = [0,1]
Output: 2
Explanation: n = 2 since there are 2 numbers, so all numbers are in the range [0,2]. 2 is the missing number in the range since it does not appear in nums.

Example 3:

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Input: nums = [9,6,4,2,3,5,7,0,1]
Output: 8
Explanation: n = 9 since there are 9 numbers, so all numbers are in the range [0,9]. 8 is the missing number in the range since it does not appear in nums.

Example 4:

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Input: nums = [0]
Output: 1
Explanation: n = 1 since there is 1 number, so all numbers are in the range [0,1]. 1 is the missing number in the range since it does not appear in nums.

Constraints:

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n == nums.length
1 <= n <= 104
0 <= nums[i] <= n
All the numbers of nums are unique.
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Symbols count in article: 870 Reading time ≈ 1 mins.

Given a sorted array A of unique numbers, find the K-th missing number starting from the leftmost number of the array.

Example 1

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Input: A = [4,7,9,10], K = 1
Output: 5
Explanation: 
The first missing number is 5.

Example 2:

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Input: A = [4,7,9,10], K = 3
Output: 8
Explanation: 
The missing numbers are [5,6,8,…], hence the third missing number is 8.

Example 3:

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Input: A = [1,2,4], K = 3
Output: 6
Explanation: 
The missing numbers are [3,5,6,7,…], hence the third missing number is 6.
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Symbols count in article: 1.9k Reading time ≈ 2 mins.

Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],…] (si < ei), find the minimum number of conference rooms required.

Example 1

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Input: [[0, 30],[5, 10],[15, 20]]
Output: 2

Example 2

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Input: [[7,10],[2,4]]
Output: 1
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