[LC] 74. Search a 2D Matrix

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

class Solution {

    public boolean searchMatrix(int[][] matrix, int target) {

        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {

            return false;

        }

        int row = matrix.length, col = matrix[0].length;

        int start = 0, end = row * col - 1;

        while (start <= end) {

            int mid = start + (end - start) / 2;

            int curRow = mid / col;

            int curCol = mid % col;

            if (matrix[curRow][curCol] == target) {

                return true;

            } else if (matrix[curRow][curCol] < target) {

                start = mid + 1;

            } else {

                end = mid - 1;

            }

        }

        return false;

    }

}

巴特西

[LC] 74. Search a 2D Matrix

最新文章

热门文章