American Express LeetCode Questions
23 questions all-time · 8 easy · 12 medium · 3 hard
| # | Problem | Difficulty | Frequency | Acceptance |
|---|---|---|---|---|
| 1 | Minimum Deletions to Make Character Frequencies Unique Hash Table, String, Greedy, Sorting | Medium | 100 | 0.6% |
| 2 | Divide an Array Into Subarrays With Minimum Cost II Array, Hash Table, Sliding Window, Heap (Priority Queue) | Hard | 98 | 0.5% |
| 3 | Maximum Equal Frequency Array, Hash Table | Hard | 98 | 0.4% |
| 4 | Find a Value of a Mysterious Function Closest to Target Array, Binary Search, Bit Manipulation, Segment Tree | Hard | 96 | 0.5% |
| 5 | Divide an Array Into Subarrays With Minimum Cost I Array, Sorting, Enumeration | Easy | 96 | 0.8% |
| 6 | Ugly Number III Math, Binary Search, Combinatorics, Number Theory | Medium | 96 | 0.3% |
| 7 | Percentage of Letter in String String | Easy | 96 | 0.8% |
| 8 | Maximize the Topmost Element After K Moves Array, Greedy | Medium | 96 | 0.2% |
| 9 | Maximum XOR After Operations Array, Math, Bit Manipulation | Medium | 96 | 0.8% |
| 10 | Equal Sum Arrays With Minimum Number of Operations Array, Hash Table, Greedy, Counting | Medium | 96 | 0.5% |
| 11 | Minimum Number of Operations to Make Array XOR Equal to K Array, Bit Manipulation | Medium | 96 | 0.9% |
| 12 | Two Sum Array, Hash Table | Easy | 83 | 0.6% |
| 13 | Valid Anagram Hash Table, String, Sorting | Easy | 78 | 0.7% |
| 14 | Longest Substring Without Repeating Characters Hash Table, String, Sliding Window | Medium | 73 | 0.4% |
| 15 | Best Time to Buy and Sell Stock Array, Dynamic Programming | Easy | 66 | 0.6% |
| 16 | Find N Unique Integers Sum up to Zero Array, Math | Easy | 66 | 0.8% |
| 17 | 3Sum Array, Two Pointers, Sorting | Medium | 56 | 0.4% |
| 18 | Rotate Array Array, Math, Two Pointers | Medium | 56 | 0.5% |
| 19 | Permutations Array, Backtracking | Medium | 56 | 0.8% |
| 20 | Isomorphic Strings Hash Table, String | Easy | 56 | 0.5% |
| 21 | Longest Common Prefix Array, String, Trie | Easy | 56 | 0.5% |
| 22 | Linked List Cycle II Hash Table, Linked List, Two Pointers | Medium | 56 | 0.6% |
| 23 | Consecutive Numbers Database | Medium | 56 | 0.5% |
How to read this list
The tabs at the top split the questions by how recently people said they were asked in interviews. "Last 30 Days" is the past month, "Last 3 Months" is the past quarter, and so on. "All Time" is every question on record for this company.
Frequency is a score from 0 to 100 for how often a question showed up in that time window. A higher number means it came up more often, so the list starts with the most common questions first. Acceptance is the share of submissions that pass on LeetCode. Click any question to open it on LeetCode.