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1️⃣ Two Sum
2️⃣ Longest Palindromic Substring
3️⃣ Merge Intervals
4️⃣ Kth Largest Element in an Array
5️⃣ LRU Cache
6️⃣ Word Break Problem
7️⃣ Find Cycle in a Linked List
8️⃣ Number of Islands
💡 Want to crack MAANG? Start solving these!
Practice Verified Codes and Commands
Two Sum (Python)
def two_sum(nums, target):
hash_map = {}
for i, num in enumerate(nums):
complement = target - num
if complement in hash_map:
return [hash_map[complement], i]
hash_map[num] = i
return []
Longest Palindromic Substring (Python)
def longest_palindromic_substring(s): def expand(l, r): while l >= 0 and r < len(s) and s[l] == s[r]: l -= 1 r += 1 return s[l+1:r] res = "" for i in range(len(s)): odd = expand(i, i) even = expand(i, i+1) res = max(res, odd, even, key=len) return res
Merge Intervals (Python)
def merge_intervals(intervals): intervals.sort(key=lambda x: x[0]) merged = [] for interval in intervals: if not merged or merged[-1][1] < interval[0]: merged.append(interval) else: merged[-1][1] = max(merged[-1][1], interval[1]) return merged
Kth Largest Element in an Array (Python)
import heapq def find_kth_largest(nums, k): return heapq.nlargest(k, nums)[-1]
LRU Cache (Python)
from collections import OrderedDict class LRUCache: def <strong>init</strong>(self, capacity): self.cache = OrderedDict() self.capacity = capacity def get(self, key): if key not in self.cache: return -1 self.cache.move_to_end(key) return self.cache[key] def put(self, key, value): if key in self.cache: self.cache.move_to_end(key) self.cache[key] = value if len(self.cache) > self.capacity: self.cache.popitem(last=False)
Find Cycle in a Linked List (Python)
class ListNode: def <strong>init</strong>(self, x): self.val = x self.next = None def has_cycle(head): slow, fast = head, head while fast and fast.next: slow = slow.next fast = fast.next.next if slow == fast: return True return False
Number of Islands (Python)
def num_islands(grid): def dfs(i, j): if i < 0 or i >= len(grid) or j < 0 or j >= len(grid[0]) or grid[i][j] == '0': return grid[i][j] = '0' dfs(i+1, j) dfs(i-1, j) dfs(i, j+1) dfs(i, j-1) count = 0 for i in range(len(grid)): for j in range(len(grid[0])): if grid[i][j] == '1': dfs(i, j) count += 1 return count
What Undercode Say
Mastering Data Structures and Algorithms (DSA) is crucial for cracking MAANG interviews. The provided problems, such as Two Sum, Longest Palindromic Substring, and LRU Cache, are foundational for understanding algorithmic thinking. Practice these problems using Python or any preferred language. Additionally, familiarize yourself with Linux commands like grep, awk, and `sed` for text processing, or Windows commands like `ipconfig` and `netstat` for network troubleshooting. For further learning, explore platforms like LeetCode, HackerRank, and GeeksforGeeks. Remember, consistent practice and understanding core concepts are key to success in technical interviews.
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initially reported by: https://www.linkedin.com/posts/sumit-yadav-08562422b_dsa-activity-7302162534587887616-wwLo – Hackers Feeds
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