Find item in sorted matrix where last number of each row is not greater than the first item of the next row.

FindKInSortedMatrix.java

public class Search2DMatrix{
    
    public boolean searchMatrix(int[][] matrix, int target) {
    
        int rows = matrix.length;
        
        if(rows <= 0) return false;
        
        int cols = matrix[0].length;
        
        if(cols <= 0) return false;
        
        int lo = 0;
        int hi = rows * cols - 1;
        
        while(lo <= hi){
            
            int mid = lo + (hi - lo)/2;
            
            int midRow = mid / cols;
            int midCol = mid % cols;
            
            if(matrix[midRow][midCol] == target) return true;
            
            else if(matrix[midRow][midCol] < target)
                lo = mid + 1;
                
            else hi = mid - 1;
        }
    
        return false;
    }
}