Search in 2D Matrix in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return false if the matrix is empty.

DSA Typescript

if (matrix.length === [1]) return false;

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A1

B0

Cnull

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Checking matrix[0].length instead of matrix.length

Returning true instead of false when empty

If the matrix has zero rows, it means it's empty, so return false.

2fill in blank

medium

Complete the code to set the number of columns in the matrix.

DSA Typescript

const cols = matrix[0].[1];

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Alength

Bsize

Ccount

Dwidth

Attempts:

3 left

💡 Hint

Common Mistakes

Using matrix.length instead of matrix[0].length

Using a non-existent property like size

The length property gives the number of columns in the first row.

3fill in blank

hard

Fix the error in the while loop condition to search correctly.

DSA Typescript

while (row < rows && col >= [1]) {

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A-1

Bcols

C0

Drows

Attempts:

3 left

💡 Hint

Common Mistakes

Using cols instead of 0, which causes out-of-bound errors

Using -1 which is invalid index

Column index should be greater or equal to 0 to stay inside matrix bounds.

4fill in blank

hard

Fill both blanks to move the search correctly in the matrix.

DSA Typescript

if (matrix[row][col] === target) return true;
else if (matrix[row][col] < target) row[1];
else col[2];

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A++

B--

C+=

D-=

Attempts:

3 left

💡 Hint

Common Mistakes

Using -- for row increment or ++ for column decrement

Using += or -= which are valid but not the simplest here

If current value is less than target, move down (row++). Else move left (col--).

5fill in blank

hard

Fill all three blanks to complete the function that searches the matrix.

DSA Typescript

function searchMatrix(matrix: number[][], target: number): boolean {
  if (matrix.length === 0) return false;
  const rows = matrix.length;
  const cols = matrix[0].[1];
  let row = 0;
  let col = cols [2] 1;
  while (row < rows && col >= [3]) {
    if (matrix[row][col] === target) return true;
    else if (matrix[row][col] < target) row++;
    else col--;
  }
  return false;
}

Drag options to blanks, or click blank then click option'

Alength

B-

C0

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using cols instead of cols - 1 for starting column

Using 1 or -1 incorrectly in loop condition

Using + instead of - for col initialization

cols is matrix[0].length; col starts at cols - 1; col must be >= 0 in loop.