74.search-a-2d-matrix.js

/*
 * @lc app=leetcode id=74 lang=javascript
 *
 * [74] Search a 2D Matrix
 *
 * https://leetcode.com/problems/search-a-2d-matrix/description/
 *
 * algorithms
 * Medium (34.76%)
 * Total Accepted:    215.8K
 * Total Submissions: 620.9K
 * Testcase Example:  '[[1,3,5,7],[10,11,16,20],[23,30,34,50]]\n3'
 *
 * Write an efficient algorithm that searches for a value in an m x n matrix.
 * This matrix has the following properties:
 * 
 * 
 * Integers in each row are sorted from left to right.
 * The first integer of each row is greater than the last integer of the
 * previous row.
 * 
 * 
 * Example 1:
 * 
 * 
 * Input:
 * matrix = [
 * ⁠ [1,   3,  5,  7],
 * ⁠ [10, 11, 16, 20],
 * ⁠ [23, 30, 34, 50]
 * ]
 * target = 3
 * Output: true
 * 
 * 
 * Example 2:
 * 
 * 
 * Input:
 * matrix = [
 * ⁠ [1,   3,  5,  7],
 * ⁠ [10, 11, 16, 20],
 * ⁠ [23, 30, 34, 50]
 * ]
 * target = 13
 * Output: false
 * 
 */
/**
 * @param {number[][]} matrix
 * @param {number} target
 * @return {boolean}
 */
var searchMatrix = function(matrix, target) {

  for (let outerIndex in matrix) {
    let lo = 0;
    let hi = matrix[outerIndex].length - 1;
    if (target < matrix[outerIndex][lo] || target > matrix[outerIndex][hi]) continue;
    for (let innerIndex in matrix[outerIndex]) {
      if (matrix[outerIndex][innerIndex] === target) return true;
    }
  }

  return false;
};