The questions below will be in a reverse-chronological order as they appeared in the interviews.

Simulated Calculator in String Processing

Calculator V1 - LC 224. Basic Calculator (Hard)

Essentially, merely +- arithmetic operations and parenthesis (nested possible) need to be supported.

Concise & efficient Solution after refactoring

Upon second thought, it appears that stack operations are need only when destructing parenthesis and processing the +- operators (see also other shared solutions on LeetCode).

Uber 60-min FE Interview - mid-July

Problem: on Hackerrank online IDE, given the function definitions, implement certain logic to obtain the expected output while ensuring the function calls running in parallel.

Note that (based on clarification made by the interviewer):

• Only JS/TS allowed for this problem;
• The function of getNameById is meant to simulate certain time consuming task; no change should be made other than under TODO inside asyncMap;
• callback param passed into getNameById is not the same as that in asyncMap.

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function getNameById(id, callback) {
  // simulating async request
  const randomRequestTime = Math.floor(Math.random() * 100) * 200;
  setTimeout(() => {
    callback("User" + id);
  }, randomRequestTime);
}

// Input
const userIds = [1, 2, 3, 4, 5];
async function asyncMap(input, iterateeFn, callback) {
  // TODO: implement this function, ensuring parallelism and the correct ordering in the output
}

asyncMap(userIds, getNameById, (names) => {
  console.log(names); // * ["user1", "user2", "user3", "user4", "user5"]
});

LRU Cache

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class Node:
    def __init__(self, key, value):
        self.prev = None
        self.next = None
        self.key = key
        self.val = value