50 Coding Patterns Every Placement Student Must Know (With Examples)

1. Two Pointers
   
   

• Reverse String – TCS Ninja
  
  

• Two Sum II – Capgemini
  
  

2. Sliding Window
   
   

• Maximum Subarray – Wipro
  
  

• Longest Substring Without Repeating Characters – Infosys
  
  

3. Fast & Slow Pointer
   
   

• Linked List Cycle – Wipro
  
  

• Middle of the Linked List – TCS Digital
  
  

4. Merge Intervals
   
   

• Merge Intervals – Infosys SP Role
  
  

5. Binary Search
   
   

• Binary Search – Capgemini
  
  

• Search Insert Position – Wipro
  
  

6. Hashing/Frequency Map
   
   

• Two Sum – TCS CodeVita
  
  

• Majority Element – Infosys
  
  

7. Prefix Sum
   
   

• Subarray Sum Equals K – Capgemini
  
  

8. Stack-Based Pattern
   
   

• Valid Parentheses – Infosys
  
  

• Daily Temperatures – Wipro
  
  

9. Recursion + Backtracking
   
   

• Subsets – Wipro Elite
  
  

• Permutations – TCS
  
  

10. Bit Manipulation
    
    

• Single Number – TCS Digital
  
  

11. Greedy Algorithm
    
    

• Jump Game – Capgemini
  
  

• Gas Station – Infosys SP
  
  

12. Dynamic Programming
    
    

• Climbing Stairs – Wipro
  
  

• House Robber – Capgemini
  
  

13. Union-Find (Disjoint Set)
    
    

• Number of Connected Components – TCS CodeVita
  
  

14. BFS (Breadth-First Search)
    
    

• Binary Tree Level Order Traversal – Infosys
  
  

15. DFS (Depth-First Search)
    
    

• Number of Islands – Capgemini
  
  

16. Topological Sort
    
    

• Course Schedule – Advanced Infosys role
  
  

17. Trie-Based Pattern
    
    

• Implement Trie – Coding contests (Capgemini)
  
  

18. Matrix Traversal
    
    

• Spiral Matrix – Wipro
  
  

19. Monotonic Stack
    
    

• Next Greater Element – Capgemini
  
  

20. Heap/Priority Queue
    
    

Kth Largest Element in an Array – Infosys

   21. In-place Reversal of Linked List

• Reverse Linked List – Infosys
  
  

22. Linked List Cycle Detection
    
    

• Linked List Cycle II – Capgemini
  
  

23. Flood Fill Algorithm
    
    

• Flood Fill – Wipro
  
  

24. Permutations and Combinations
    
    

• Letter Case Permutation – TCS Digital
  
  

25. Subsets Pattern
    
    

• Subsets II – Infosys SP
  
  

26. Rotate Array/String Pattern
    
    

• Rotate Array – Capgemini
  
  

27. Minimum/Maximum in Sliding Window (Deque)
    
    

• Sliding Window Maximum – Advanced Wipro roles
  
  

28. Backtracking with Constraints
    
    

• N-Queens – Infosys HackWithInfy
  
  

29. Greedy with Sorting
    
    

• Minimum Number of Arrows to Burst Balloons – Capgemini
  
  

30. Segment Tree Pattern (Range Query)
    
    

• Range Sum Query – Mutable – Advanced TCS CodeVita
  
  

31. Kadane’s Algorithm
    
    

• Maximum Subarray – Wipro
  
  

32. Two Heaps
    
    

• Find Median from Data Stream – Capgemini
  
  

33. Binarization Techniques
    
    

• Find Minimum in Rotated Sorted Array – TCS Digital
  
  

34. Recursive Tree Traversals
    
    

• Binary Tree Inorder Traversal – Infosys
  
  

35. Iterative Tree Traversals
    
    

• Binary Tree Postorder Traversal – Capgemini
  
  

36. LCA (Lowest Common Ancestor)
    
    

• Lowest Common Ancestor of a Binary Tree – Wipro
  
  

37. Diameter of a Tree
    
    

• Diameter of Binary Tree – Infosys
  
  

38. Count Paths Pattern
    
    

• Unique Paths – TCS
  
  

39. Graph Coloring
    
    

• Is Graph Bipartite? – Capgemini
  
  

40. K-way Merge
    
    

• Merge k Sorted Lists – Infosys
  
  

41. Cycle Detection in Graph
    
    

• Course Schedule II – Capgemini
  
  

42. Top K Elements Pattern
    
    

• Top K Frequent Elements – Wipro
  
  

43. Jump Game / Reachability
    
    

• Jump Game II – Infosys
  
  

44. Median in Stream (Two Heap)
    
    

• Find Median from Data Stream – Capgemini
  
  

45. Longest Palindromic Substring
    
    

• Longest Palindromic Substring – TCS Digital
  
  

46. Rabin Karp / Rolling Hash
    
    

• Implement strStr() – TCS Ninja
  
  

47. Shortest Path Algorithm (Dijkstra)
    
    

• Network Delay Time – Infosys
  
  

48. Bellman-Ford Algorithm
    
    

• Cheapest Flights Within K Stops – Capgemini
  
  

49. Floyd Warshall Algorithm
    
    

• Minimum Distance Between Two Cities – Advanced Coding Tests
  
  

50. Minimax / Game Theory Pattern
    
    

Predict the Winner – Infosys SP Role