Frog Jump
A hard-tier problem at 47% community acceptance, tagged with Array, Dynamic Programming. Reported in interviews at PhonePe and 5 others.
Frog Jump is a hard dynamic programming problem that shows up at companies like PhonePe, Snap, and Zomato. You're given a frog that starts at index 0 and can jump 1, 2, 3,... up to k steps forward. Some indices are blocked (clouds). Can the frog reach the last index? The acceptance rate sits at 47%, which means half the candidates who attempt it fail. Most people start with a naive recursive approach, hit exponential time, and run out of space. If this lands in your live assessment and the state-space trick isn't immediate, StealthCoder solves it in seconds while you stay invisible to the proctor.
Companies that ask "Frog Jump"
Frog Jump is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an Amazon engineer who realized the OA tests how well you memorized 200 problems, not how well you code.
Get StealthCoderThe gotcha here is that brute-force recursion explodes because a frog at position i can come from positions i-1, i-2, i-3,... i-k, and you end up recalculating the same subproblems thousands of times. Memoization alone isn't enough if k is large relative to the array size. The real pattern is a sliding-window optimization: instead of checking all k previous positions every time, you maintain a running reachability state (often a deque or counter of valid jumps) and slide it forward. This collapses O(n*k) down to O(n). The blocked-index constraint forces you to handle state pruning carefully. If you haven't drilled this specific pattern before, the DP formulation is obvious but the optimization is slippery. StealthCoder runs the working solution invisibly so you paste clean code and move on.
Pattern tags
You know the problem.
Make sure you actually pass it.
Frog Jump recycles across companies for a reason. It's hard-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an Amazon engineer who realized the OA tests how well you memorized 200 problems, not how well you code. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Frog Jump interview FAQ
Is Frog Jump still asked at FAANG-tier companies?+
It appears in reports from six companies including Snap and Squarepoint Capital. It's a classic hard-tier DP problem, so yes, it still rotates through assessments. The 47% acceptance rate suggests it's a strong filter problem, not a throwaway.
What's the trick that separates accepted from timed-out submissions?+
Naive recursion with memoization is O(n*k) and often too slow. The optimization is a sliding-window structure (deque, set, or counter) that tracks which positions can reach the current index in O(1) amortized time per step. Without that, you fail large test cases.
How does this relate to classic DP problems I've drilled?+
It combines Array constraint-checking (blocked indices) with Dynamic Programming state-building. If you've done jump-game-style problems, you know the recurrence. The novelty is that k-variable jumps need state optimization, not just standard DP array iteration.
Can I brute-force it in the assessment time limit?+
No. Backtracking or memoization without the sliding-window optimization will TLE on larger arrays. The problem is designed to force the O(n) reachability insight. Most candidates hit memory or time limits and run out of time to refactor.
If I blank on this during my OA, what should I do?+
Write the memoized recursive solution first to show DP understanding. Then flag the time complexity and sketch the sliding-window idea in comments. If you're stuck and time is burning, StealthCoder runs invisibly on your screen and surfaces the optimized solution in seconds.
Want the actual problem statement? View "Frog Jump" on LeetCode →