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

// 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 in ascending from left to right.
// Integers in each column are sorted in ascending from top to bottom.
//
//
//
//
// For example,
//
// Consider the following 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]
// ]
//
//
// Given target = 5, return true.
// Given target = 20, return false.


/**
 * @param {number[][]} matrix
 * @param {number} target
 * @return {boolean}
 */
var searchMatrix = function(matrix, target) {
    var row = matrix.length - 1;
    var length = matrix[0].length;
    var col = 0;
    while(row >= 0 && col < length) {
        if (matrix[row][col] === target) {
            return true;
        } else if (matrix[row][col] > target) {
            row -= 1;
        } else {
            col += 1;
        }
    }
    return false;
};