README.md

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

Solutions (Rust)

1. Binary Search

impl Solution {
    pub fn search_matrix(matrix: Vec<Vec<i32>>, target: i32) -> bool {
        if matrix.len() == 0 {
            return false;
        }

        let m = matrix.len();
        let n = matrix[0].len();
        let mut l = 0;
        let mut r = m * n;

        while l < r {
            let mid = (l + r) / 2;
            let row = mid / n;
            let col = mid % n;

            if target == matrix[row][col] {
                return true;
            } else if target < matrix[row][col] {
                r = mid;
            } else {
                l = mid + 1;
            }
        }

        false
    }
}