Mock Interview: Solve It Like You're on the Call

Hear what a strong answer sounds like

Here's how a strong candidate talks through this problem. Read it out loud once, then do the practice step the same way.

Clarify: "So for each index I multiply every other element? Can there be zeros or negatives? Can I use extra space for the output?"

Example: "For [1, 2, 3, 4], index 0 is 2·3·4 = 24, index 1 is 1·3·4 = 12…"

Brute force: "For each index, multiply all the others. That's two nested loops, O(n²)."

Insight: "Each answer is everything to the left times everything to the right. I can compute running products from both directions in two passes."

Complexity: "O(n) time, O(1) extra space apart from the output."

Test: "With a zero, like [2, 0, 5]: left products are [1, 2, 0], right products [0, 5, 1], giving [0, 10, 0]. ✓"

See the two passes

const nums = [1, 2, 3, 4];
const left = [], right = [];
let acc = 1;
for (const n of nums) { left.push(acc); acc *= n; }
acc = 1;
for (let i = nums.length - 1; i >= 0; i--) { right[i] = acc; acc *= nums[i]; }
console.log("left: ", left);
console.log("right:", right);
console.log("answer:", left.map((l, i) => l * right[i]));

Make mock interviews a habit

• On your own: record yourself solving an Interview Prep question out loud, then watch it back. You'll spot every silent stretch
• With a friend: take turns as interviewer, using Interview Prep questions
• Record yourself solving a problem out loud. Awkward, but you'll instantly hear where you go quiet

After every mock, write down one thing to improve. Ten deliberate mocks will change how you perform on the real call.