Longest Increasing Path in a Matrix


Given an m x n integers matrix, return the length of the longest increasing path in matrix.
From each cell, you can either move in four directions: left, right, up, or down. You may not move diagonally or move outside the boundary (i.e., wrap-around is not allowed).
Example 1: Input: matrix = [[9,9,4],[6,6,8],[2,1,1]] Output: 4 Explanation: The longest increasing path is [1, 2, 6, 9].
Example 2: Input: matrix = [[3,4,5],[3,2,6],[2,2,1]] Output: 4 Explanation: The longest increasing path is [3, 4, 5, 6]. Moving diagonally is not allowed.

Example 3: Input: matrix = [[1]] Output: 1
Constraints: m == matrix.length n == matrix[i].length 1 <= m, n <= 200 0 <= matrix[i][j] <= 231 - 1 #leetcode #hard
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