PayPal OA 2026 满分指南 – SDE 题库、SQL 真题与 Codility 代写

Many students feel that Fintech interviews are no less difficult than those at big firms.PayPal就是其中之一。最近我们 Programhelp 收到了多位准备 PayPal OA 的同学咨询，包括已经收到在线笔试邀请、准备走内推通道的、以及多次刷题仍然感觉没有”考试感”的同学。结合这些真实学员的练习反馈和我们过往积累的 PayPal 高频题库，这篇就来帮大家全面拆解 PayPal OA 的出题风格、常见难点和解题思路。如果你正在准备PayPal的面试，那么接着往下看吧~

PayPal SDE II OA Basic Information

PayPal's SDE II positions are usually for engineers with 2 to 5 years of development experience, so the difficulty, question design, and dimension of the OA section will be a bit higher compared to the school recruiting. Below are the key points and forms of the OA process that have been organized recently:

1. Examination platform

Codility: Most SDE II positions at PayPal utilize the Codility platform, and some positions (especially related to data platforms/risk control platforms) also have use of HackerRank.

Examination environment: Turn on Camera + Screen Monitor, do not allow screen cut or open other programs, the system automatically records mouse/keyboard/screen cut behavior.

2. Structure of the topic

Question volume: 3 programming questions

Time limit: 90 minutes to complete all questions

Question Difficulty Distribution:

An Easy-Medium question to warm up or test basic skills (e.g. string processing, array scanning);

A Medium question, often with Hash / Stack / Queue applications;

A Medium-Hard or Hard level question covering high-frequency interview topics such as graphs, concurrent sets, shortest paths, and dynamic programming.

bonus points: Behaviors such as writing complete annotations, providing multiple test samples, and optimizing time complexity can sometimes be used as a basis for screening.

3. Scoring criteria

PayPal 的 OA 不只是刷题刷过就行，判分真的挺细的～像是有没有过所有测试用例、时间复杂度有没有写好、边界情况有没有考虑到（比如空输入、重复数字这种），这些都是基础要求 。另外代码风格也会看，变量名清不清楚、函数写得整不整洁，都可能影响整体印象。比较隐蔽的一点是——系统其实会记录你提交的次数和频率，如果你来回改太多次，也可能被认为思路不清晰 or 稳定性差。所以想拿高分，题要刷透，更要写得”像个工程师”才行！

4. Frequently asked questions

Sliding window, stack/queue handling

Hash tables + double traversal

Concurrent set search, graph search (DFS/BFS)

Minimum spanning tree, topological ordering

Simplified versions of system simulation questions (e.g., Task Scheduler, Job Queue)

Core algorithm optimization (e.g., O(n^2) to O(nlogn) reconstruction)

PayPal OA Real Question Reduction + Solution Ideas

Title 1: Vowels

Given a string array that contains N elements, each composed of lowercase English letters, and q queries, each query of the format l - r. For each query, determine how many strings starting from index l and ending at index r have vowels as the first and last character. Vowels are in {a, e, i, o, u}.

Example:
strArr = ["aba", "bcb", "ece", "aa", "e"]
queries = ["1 - 3", "2 - 5", "2 - 2"]

These strings represent two dash - delimited integers l And r, the start and end indices of the interval, inclusive. Using 1 - based indexing in the string array.

• The interval 1 - 3 contains two strings that start and end with a vowel. aba And ece.
• The interval 2 - 5 also has three.
• The third interval, from 2 - 2, the only element in the interval, and the only element in the interval, and the only element in the interval, and the only element in the interval. bcb, does not begin and end with a vowel.

The return array for the queries is [2, 3, 0].

Function Description
Complete the hasVowels function in the editor below. It must return an array of integers that represent the result of each query in the order.

#include <bits/stdc++.h>
using namespace std;

/*
 * Complete the 'hasVowels' function below.
 *
 * The function is expected to return an INTEGER_ARRAY.
 * The function accepts following parameters:
 *  1. STRING_ARRAY strArr
 *  2. STRING_ARRAY query
 */

vector<int> hasVowels(vector<string> strArr, vector<string> query) {
    
}

int main() {
    
}

Title 2: First Unique Character

A unique character is one that appears only once in a string. Given a string consisting of lowercase English letters only, return the index of the first Given a string consisting of lowercase English letters only, return the index of the first occurrence of a unique character in the string using 1 - based indexing. If the string does not contain any unique character, return -1.

Example:
s = "statistics"

The unique characters are [a, c] among which A Using 1 - based indexing, it is at index 3.

Function Description
Complete the function getUniqueCharacter in the editor below.

#include <bits/stdc++.h>
using namespace std;

/*
 * Complete the 'getUniqueCharacter' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts STRING s as parameter.
 */

int getUniqueCharacter(string s) {
    
}

int main() {
    
}

Topic 3: Load on systems

There are 7 computers in a network numbered from 0 to 6. Each network request is assigned to one of those computers. Hash function used for that is h(id) = id % 7. Which computer will have maximum load if the request ids are. 17, 27, 16, 5, 11, 13, 9, 23, 25

Pick ONE option.

• 6
• 0 and 1
• 2
• 4 and 5

Topic 4: Find the value

What will be the value of x after the execution of the following code.

int x = 1;
for (int i = 1; i <= 128; i += i) {
    x += x;
}

Pick ONE option.

• 64
• 48
• 256
• 128

Topic 5: Time Complexity of Searching a Linked List

What is the time complexity to find an element in a linked list of length N?

Pick ONE option.

• O(log₂n)
• O(n)
• O(1)
• O(n²)

Topic 6: Aggregate Marks

There is a database containing the marks of some students in various subjects. The data may contain any number of subjects for a student.

Retrieve the records of students who have a sum of marks greater than or equal to 500. The result should be in the following format. STUDENT_ID, SUM_OF_MARKS sorted descending by STUDENT_ID.

Schema
(Sample Data Table not fully shown, but SQL query framework is given)

-- Enter your query below. Please append a semicolon ';' at the end of the query
SELECT STUDENT_ID, SUM(MARKS) AS SUM_OF_MARKS
FROM marks
GROUP BY STUDENT_ID
HAVING SUM(MARKS) >= 500
ORDER BY STUDENT_ID DESC;

Topic 7: SQL Join

The Venn diagram below illustrates a JOIN operation on table A And B. The shaded area is the records returned by the operation.

Which type of JOIN will produce such result?

Pick ONE option.

• INNER JOIN
• LEFT JOIN

Recommendations

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Jack Xu MLE | Microsoft Artificial Intelligence Technician

Ph.D. From Princeton University. He lives overseas and has worked in many major companies such as Google and Apple. The deep learning NLP direction has multiple SCI papers, and the machine learning direction has a Github Thousand Star⭐️ project.

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