Dezerv | Backend Engineer | Rejected
Question Details
Round 1 OA 2 Coding question Round 2 Coding round You are given a triangular array/list \'TRIANGLE\'. Your task is to return the minimum path sum to reach from the top to the...
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Round 1 OA
2 Coding question
Round 2 Coding round
You are given a triangular array/list \'TRIANGLE\'. Your task is to return the minimum path sum to reach from the top to the bottom row.
The triangle array will have N rows and the i-th row, where 0 <= i < N will have i + 1 elements.
You can move only to the adjacent number of rows below each step. For example, if you are at index j in row i, then you can move to j or j + 1 index in row i + 1 in each step.
If the array given is \'TRIANGLE\' = [[1], [2,3], [3,6,7], [8,9,6,1]] the triangle array will look like:
1
2,3
3,6,7
8,9,6,10
For the given triangle array the minimum sum path would be 1->2->3->8. Hence the answer would be 14.
Round 3 LLD
Mandate Problem
Mandates act as tokens for standing instructions with bank. It will enable the merchant to debit money from customer\u2019s bank account. Standing instructions based on credit card are facilitated by VISA/Master/Rupay/Amex networks. NPCI facilitates internet banking based standing instructions - which is linked with customer bank account. There are different payment gateways which works as a middleman to integrate with NPCI. We can use mandate to make a debit from customer\u2019s account for making investments, both lumpsum and sips. Prepare the LLD to integrate with a payment gateway to setup mandate and use the same in different flows.
Flow - Data ecah component
API -
DB schema
About This Question
This is a reported interview question from a american express interview for a backend role during the oa round reported in 2024.
More American Express Interview Questions
About American Express Interview Reports
This question was reported by a candidate who interviewed at American Express. LeakCode aggregates interview reports from 10+ sources, including 1Point3Acres, Glassdoor, LeetCode Discuss, Blind, Reddit, Indeed, and Nowcoder. Each report is translated where necessary, deduplicated against existing entries, and tagged by company, role, round type, and reporting date.
Use this question as one calibration data point, not a memorization target. Companies typically rotate their question pools every 2-4 months; the exact wording of a 2024 question may differ from what you encounter today. The underlying pattern, difficulty level, and follow-up depth at American Express are the higher-signal extractions to take from this report.
For broader preparation context, the American Express interview process typically includes a recruiter screen, one or two technical phone screens, and a 4-5 round on-site loop covering coding, system design (at L4+ levels), and behavioral. Reports tagged on LeakCode show the round-by-round distribution and typical difficulty calibration. To browse questions filtered by round type and seniority, use the company hub linked above.
How To Practice This Type of Question
Solve similar problems on LeetCode under timed conditions (25-35 minutes per medium difficulty). The goal is pattern recognition: recognize the underlying technique (sliding window, two-pointer, BFS, memoized recursion, etc.) within 60-90 seconds of reading. Strong candidates verbalize their hypothesis out loud before coding, then iterate based on feedback. Weak candidates dive into implementation immediately, lose time on the wrong approach, and run out of time for follow-ups.
Companies update their question pools every 2-4 months. The exact wording of any given question may have been retired by the time you interview. Focus your prep on the pattern, not the specific problem. The patterns that appear in American Express reports consistently are the ones worth investing in; one-off niche problems are not.
During Your American Express Round
Apply the standard interview round template: clarify requirements (2-3 minutes), state your approach out loud and confirm direction with the interviewer (3-5 minutes), code with narration (15-25 minutes), test with concrete examples including edge cases (5 minutes), discuss optimization or trade-offs if time permits (5 minutes). This template is universally accepted across FAANG and adjacent companies; deviating from it produces weaker interviewer feedback signal.
The single most predictive failure mode in American Express reports tagged "no hire": not asking clarifying questions. Interviewers are explicitly trained to weight this. Strong candidates ask 3-5 clarifying questions even on problems that look obvious; weak candidates dive into code immediately. The clarifying-question check is often the first signal recorded in the interviewer's written notes.