[Leetcode] [JavaScript] Search a 2D Matrix

Search a 2D Matrix

Write an efficient algorithm, searches for a value in a m x n Matrix. This matrix has the following properties:

• Integers in each row is sorted from the left to the right.
• The first integer of each row was greater than the last integer of the previous row.

For example,

Consider the following matrix:

[
  [1,   3,  5,  7],
  [10, 11, 16, 20],
  [23, 30, 34, 50]
]

Given target =3, returntrue.

https://leetcode.com/problems/search-a-2d-matrix/

Although it is a two-dimensional array, ordered, as a one-dimensional array of two points, calculate the row and Col subscript.

If you use the wrong two times, do a row at a time to do the column, it is very complicated to write.

 
 
1 /**
 2  * @param {number[][]} matrix
 3  * @param {number} target
 4  * @return {boolean}
 5  */
 6 var searchMatrix = function(matrix, target) {
 7     var m = matrix.length, n = matrix[0].length;
 8     var i  = 0, j = m * n - 1, middle, row, col, curr;
 9     while(i <= j){
10         middle = parseInt((i + j) / 2);
11         row = parseInt(middle / n);
12         col = middle % n;
13         curr = matrix[row][col];
14         if(target === curr){
15             return true;
16         }
17 
18         if(target > curr){
19             i = middle + 1; 
20         }else{
21             j = middle - 1;
22         }    
23     }
24     return false;
25 };

[Leetcode] [JavaScript] Search a 2D Matrix