Word Search in Grid Using Backtracking in DSA C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main idea behind using backtracking for word search in a grid?

Backtracking tries all possible paths in the grid to find the word by moving step-by-step and undoing moves if they don't lead to a solution.

beginner

In a word search grid, how do we ensure we don't use the same cell twice in one word path?

We mark the cell as visited during the current path and unmark it when backtracking to allow other paths to use it.

beginner

What directions are typically checked when searching for the next character in the grid?

We check up, down, left, and right neighbors of the current cell to find the next character.

intermediate

Why is backtracking suitable for word search problems in grids?

Because it explores all possible paths systematically and stops when the word is found or all options are exhausted.

intermediate

What is the base case in the recursive backtracking function for word search?

The base case is when all characters of the word have been matched successfully, meaning the word is found.

Which of the following is NOT a valid move when searching for the next character in the grid?

A Moving up

B Moving diagonally

C Moving left

D Moving right

Typically, only up, down, left, and right moves are allowed, not diagonal moves.

What should you do if the current cell's character does not match the word's current character?

A Backtrack and try a different path

B Return true immediately

C Mark the cell as visited

D Continue searching neighbors

If the character does not match, backtracking means undoing the current step and trying other paths.

How do you prevent revisiting the same cell in the current search path?

A Mark cells as visited temporarily during the current path

B Ignore visited cells permanently

C Use a global visited array without resetting

D Do not check neighbors

Cells are marked visited only during the current path and unmarked when backtracking.

What does the backtracking function return when the entire word is found?

A The length of the word

B False

C True

D The current position

It returns true to indicate the word has been found.

Which data structure is commonly used to keep track of visited cells in the grid?

A Stack

B Queue

C Linked list

D 2D boolean array

A 2D boolean array matching the grid size is used to mark visited cells.

Explain how backtracking works to find a word in a grid step-by-step.

Think about trying paths and undoing moves if they don't work.

Describe how you would implement a function to check if a word exists in a grid using backtracking.

Focus on recursion and visited tracking.