Jump Game Problem in DSA Typescript - Practice Problems & Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Jump Game Reachability Check

What is the output of this TypeScript code that checks if you can jump to the last index?

DSA Typescript

function canJump(nums: number[]): boolean {
  let maxReach = 0;
  for (let i = 0; i < nums.length; i++) {
    if (i > maxReach) return false;
    maxReach = Math.max(maxReach, i + nums[i]);
  }
  return true;
}

console.log(canJump([2,3,1,1,4]));

A SyntaxError

B false

C true

D TypeError

💡 Hint

Think about whether the jumps allow reaching the last index.

The function tracks the furthest index reachable. Since the input allows jumps to the end, it returns true.

❓ Predict Output

intermediate

Output when jump is blocked early

What does this code print when the jump is blocked early?

DSA Typescript

function canJump(nums: number[]): boolean {
  let maxReach = 0;
  for (let i = 0; i < nums.length; i++) {
    if (i > maxReach) return false;
    maxReach = Math.max(maxReach, i + nums[i]);
  }
  return true;
}

console.log(canJump([3,2,1,0,4]));

A false

B true

C RangeError

D undefined

💡 Hint

Check if the zero blocks further progress.

The zero at index 3 blocks reaching index 4, so the function returns false.

🔧 Debug

advanced

Identify the error in jump game code

What error does this code produce when run?

DSA Typescript

function canJump(nums: number[]): boolean {
  let maxReach = 0;
  for (let i = 0; i <= nums.length; i++) {
    if (i > maxReach) return false;
    maxReach = Math.max(maxReach, i + nums[i]);
  }
  return true;
}

console.log(canJump([2,3,1,1,4]));

A SyntaxError

B TypeError: Cannot read property 'undefined' of undefined

C RangeError: Maximum call stack size exceeded

D No error, outputs true

💡 Hint

Check the loop boundary and array access.

The loop goes one index too far (i <= nums.length), accessing nums[nums.length] which is undefined. This leads to NaN in the maxReach calculation (since Math.max with NaN returns NaN), and attempting to access nums[i] when i is out of bounds causes a TypeError.

🧠 Conceptual

advanced

Minimum jumps to reach the end

Given an array where each element represents max jump length at that position, what is the minimum number of jumps to reach the last index for [2,3,1,1,4]?

A 2

B 3

C 4

D 1

💡 Hint

Try to jump the farthest possible at each step.

Jump from index 0 to 1, then from 1 to 4, total 2 jumps.

🚀 Application

expert

Output of jump game with zero at start

What is the output of this code when the first element is zero?

DSA Typescript

function canJump(nums: number[]): boolean {
  let maxReach = 0;
  for (let i = 0; i < nums.length; i++) {
    if (i > maxReach) return false;
    maxReach = Math.max(maxReach, i + nums[i]);
  }
  return true;
}

console.log(canJump([0,1,2]));

A true

B IndexError

C SyntaxError

D false

💡 Hint

If you cannot move from the start, you cannot reach the end.

Since the first element is zero, you cannot move anywhere, so the function returns false.