60 lines
1.4 KiB
Markdown
60 lines
1.4 KiB
Markdown
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# Leetcode Search-A-2D-Matrix-II
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2022-09-03 14:57
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> ##### Algorithms:
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> #algorithm #divide_and_conquer
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> ##### Data structures:
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> #DS #array
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> ##### Difficulty:
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> #coding_problem #difficulty-medium
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> ##### Additional tags:
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> #leetcode
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> ##### Revisions:
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> N/A
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##### Links:
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- [Link to problem](https://leetcode.com/problems/search-a-2d-matrix-ii/)
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___
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### Problem
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Write an efficient algorithm that searches for a value `target` in an `m x n` integer matrix `matrix`. This matrix has the following properties:
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- Integers in each row are sorted in ascending from left to right.
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- Integers in each column are sorted in ascending from top to bottom.
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#### Examples
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**Example 1:**
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```
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**Input:** matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 5
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**Output:** true
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```
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**Example 2:**
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```
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**Input:** matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 20
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**Output:** false
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```
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#### Constraints
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### Thoughts
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> [!summary]
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> This is a #divide_and_conquer problem.
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It's divide and conquer, because every time we do a action,
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the problem is smaller.
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Start from the top-right, (alternatively, bottom-left),
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because walking left makes the number smaller, and down makes the number bigger.
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### Solution
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