74. Search a 2D Matrix

[Tcdian]

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

Example 3

Input: matrix = [], target = 0
Output: false

Constraints

• m == matrix.length
• n == matrix[i].length
• 0 <= m, n <= 100
• -10⁴ <= matrix[i][j], target <= 10⁴

[Tcdian]

Solution

• TypeScript Solution

function searchMatrix(matrix: number[][], target: number): boolean {
    if (_.isEmpty(matrix) || _.isEmpty(_.first(matrix))) {
        return false;
    }
    let x = 0;
    let y = matrix[0].length - 1;
    while (x < matrix.length && y >= 0) {
        if (matrix[x][y] < target) {
            x++;
        } else if (matrix[x][y] > target) {
            y--;
        } else {
            return true;
        }
    }
    return false;
};