Leetcode 240. Search a 2D Matrix II

  • Integers in each row are sorted in ascending from left to right.
  • Integers in each column are sorted in ascending from top to bottom.
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
Output: true
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
Output: false
  • m == matrix.length
  • n == matrix[i].length
  • 1 <= n, m <= 300
  • -109 <= matix[i][j] <= 109
  • All the integers in each row are sorted in ascending order.
  • All the integers in each column are sorted in ascending order.
  • -109 <= target <= 109
  1. easy scan all the matrix, if find the number equal to target return true, else return false.
  1. T(m+n)
  2. get the top right corner number, if it’s smaller than target, move to next row; if it’s bigger than target, move to left column

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Gary Chiang

Gary Chiang

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CS new grad, 6 years experience related to supply chain management. Located in Bay area