LeetCode Kaise Solve Kare 2026: Beginner Guide

Aapne LeetCode open kiya, “Two Sum” dekha, solution samjha bhi, next day same question phir blank. Phir YouTube pe 3 videos, 2 playlists, ek DSA sheet, aur dimaag mein sirf ek thought: “Bhai coding interviews mere bas ki baat nahi hai kya?”

Relax. 2026 mein bhi LeetCode ka game same hai, bas competition zyada sharp ho gaya hai. TCS Ninja se lekar Infosys Specialist Programmer, Wipro Turbo, Razorpay, PhonePe, Swiggy, Zomato, Paytm jaise product companies tak, coding round mein DSA ka basic to medium level strong hona chahiye.

Agar tu beginner hai, toh LeetCode solve karna “random questions maaro” wala kaam nahi hai. Iske liye system chahiye, pattern chahiye, aur patience chahiye. Is guide mein main tujhe bilkul practical way mein bataunga: LeetCode kaise start kare, kaunse topics pehle kare, daily routine kya ho, aur interview-ready kaise bane.

LeetCode actually hai kya, aur itna hype kyun hai?#

LeetCode ek coding practice platform hai jahan tum Data Structures and Algorithms, yani DSA problems solve karte ho. Companies ke coding rounds aur technical interviews mein similar pattern ke questions aate hain.

Matlab exact question same na bhi aaye, logic same family ka hota hai.

Example:

1. Array mein pair find karna
2. String ko reverse ya validate karna
3. Linked List mein cycle detect karna
4. Tree traversal karna
5. Graph mein shortest path find karna
6. Dynamic Programming se optimized answer nikalna

Ye skills companies ko dikhati hain ki tum problem ko logically tod sakte ho ya nahi.

Indian job market mein LeetCode ka role

Aajkal fresher roles mein bhi coding round normal ho chuka hai. Chahe tum service company target karo ya product company.

Rough salary idea dekho:

1. TCS Ninja: ₹3.3 LPA se ₹4 LPA
2. TCS Digital: ₹7 LPA ke around
3. Infosys Specialist Programmer: ₹9.5 LPA ke around
4. Wipro Turbo: ₹6 LPA se ₹8 LPA
5. Zoho: ₹6 LPA se ₹12 LPA
6. Paytm fresher SDE: ₹10 LPA se ₹18 LPA
7. Razorpay, PhonePe, Swiggy, Zomato SDE roles: ₹18 LPA se ₹35 LPA tak possible

Ab obvious baat hai, ₹4 LPA aur ₹20 LPA role ke interview ka level same nahi hoga. But base DSA sab jagah kaam aata hai.

Sabse pehle: Language choose karo, language pe overthinking mat karo#

Beginner sabse pehle yahi doubt mein atak jaata hai: “DSA ke liye C++ karu, Java karu, ya Python?”

Simple answer: jis language mein tum comfortable ho, usi se start karo.

Best options for LeetCode

1. C++

   • Fast hoti hai
   • STL se arrays, maps, sets, priority queue easy ho jaate hain
   • Competitive programming wale students ke liye best

2. Java

   • Indian colleges mein common hai
   • Backend jobs mein useful hai
   • OOP concepts strong karne mein help milti hai

3. Python

   • Syntax easy hai
   • Beginners ke liye quick learning
   • Product interviews mein accepted hai, bas complexity ka dhyan rakhna

Agar tu bilkul beginner hai, Python se start kar sakta hai. Agar tu engineering student hai aur placements target kar raha hai, Java ya C++ bhi safe choice hai.

Mera practical suggestion:

• College 1st or 2nd year: C++ ya Java
• Final year with less time: Python
• Already Java jaante ho: Java continue karo
• Competitive programming bhi karni hai: C++

Beginner mistake: Direct hard questions pe jump#

LeetCode pe jaate hi log “Google interview question” search karte hain, phir Hard DP question kholte hain, phir depression.

Bhai, gym mein first day 120 kg deadlift nahi maarte. Pehle form banta hai.

LeetCode difficulty ko aise samjho

1. Easy

   • Basic syntax, loops, arrays, hash maps, strings
   • Interview mein warm-up ya screening level

2. Medium

   • Real interview ka main zone
   • Patterns strong hone chahiye
   • Arrays, sliding window, binary search, trees, graphs, DP

3. Hard

   • Top product companies, advanced rounds
   • Har role ke liye required nahi
   • Beginner ke liye starting mein avoid karo

Tumhara pehla target hona chahiye:

• 100 Easy
• 150 Medium
• 20 Hard, woh bhi baad mein

But number se zyada pattern important hai. 300 random questions solve karne se better hai 150 pattern-wise questions karna.

LeetCode ka correct roadmap 2026 ke liye#

Ab main tujhe beginner-friendly order de raha hoon. Is order mein chaloge toh confusion kam hoga.

Phase 1: Programming basics pakka karo#

Agar tum loops, functions, arrays, strings mein struggle karte ho, LeetCode pe mat jump karo. Pehle foundation theek karo.

Tumhe ye topics aane chahiye

1. Variables, data types
2. If-else
3. Loops
4. Functions
5. Arrays or lists
6. Strings
7. Hash map or dictionary
8. Basic recursion
9. Time complexity basics
10. Space complexity basics

Practice ke liye simple tasks

1. Array ka max element find karo
2. String reverse karo
3. Prime number check karo
4. Frequency count nikalo
5. Duplicate element find karo
6. Palindrome check karo
7. Factorial using recursion likho

Jab tak ye cheezein bina YouTube dekhe likh pa rahe ho, tab LeetCode pe real start karo.

Phase 2: Arrays and Hashing#

Arrays LeetCode ka bread-butter hai. Har dusra question array ya hash map se linked hota hai.

Must-do patterns

1. Two Sum
2. Contains Duplicate
3. Best Time to Buy and Sell Stock
4. Product of Array Except Self
5. Maximum Subarray
6. Majority Element
7. Group Anagrams
8. Top K Frequent Elements

Kaise solve kare

Har question mein yeh 5 step follow karo:

1. Problem statement dhyan se read karo
2. Example manually dry run karo
3. Brute force socho
4. Better approach socho using hash map, sorting, prefix sum
5. Code likho aur edge cases test karo

Example: Two Sum ka thinking

Problem: Array diya hai, target diya hai, do numbers ke indices find karo jinka sum target ho.

Brute force:

• Har pair check karo
• Time: O(n²)

Optimized:

• Hash map use karo
• Har number ke liye target minus number check karo
• Time: O(n)

Yahi LeetCode ka real learning hai. Sirf answer yaad mat karo, brute se optimized tak ka journey samjho.

Phase 3: Two Pointers and Sliding Window#

Yeh dono patterns interviews mein bahut popular hain. Especially strings aur arrays mein.

Two Pointers kab use hota hai?

Jab sorted array ho, ya pair/triplet find karna ho, ya start-end se process karna ho.

Must-do questions:

1. Valid Palindrome
2. Two Sum II
3. 3Sum
4. Container With Most Water
5. Move Zeroes
6. Remove Duplicates from Sorted Array

Sliding Window kab use hota hai?

Jab contiguous subarray ya substring ka question ho.

Keywords pe dhyan do:

• longest
• shortest
• subarray
• substring
• at most k
• no repeating
• maximum sum

Must-do questions:

1. Maximum Sum Subarray of Size K
2. Longest Substring Without Repeating Characters
3. Minimum Window Substring
4. Longest Repeating Character Replacement
5. Permutation in String
6. Max Consecutive Ones III

Sliding Window ka basic formula

1. Right pointer se window expand karo
2. Condition break ho toh left pointer se shrink karo
3. Har valid window pe answer update karo

Beginner ko sliding window initially tough lagta hai. Normal hai. Same pattern ke 10 questions karo, suddenly click karega.

Phase 4: Stack and Queue#

Stack questions mein “last in first out” logic hota hai. Queue mein “first in first out”.

Stack ke common use cases

1. Parentheses validation
2. Next greater element
3. Monotonic stack
4. Expression evaluation
5. Undo type logic

Must-do stack questions:

1. Valid Parentheses
2. Min Stack
3. Daily Temperatures
4. Next Greater Element
5. Largest Rectangle in Histogram
6. Evaluate Reverse Polish Notation

Queue ke common use cases

1. BFS traversal
2. Level order traversal
3. Sliding window maximum
4. Task scheduling

Must-do queue questions:

1. Implement Queue using Stacks
2. Number of Recent Calls
3. Binary Tree Level Order Traversal
4. Rotting Oranges
5. Sliding Window Maximum

Stack and queue boring lag sakte hain, but interviews mein yeh easy marks dete hain.

Phase 5: Binary Search, sirf sorted array nahi#

Most beginners sochte hain binary search sirf sorted array mein mid nikalne ka naam hai. Actually interviews mein binary search answer space pe bhi hota hai.

Basic binary search template

1. low = 0
2. high = n - 1
3. while low ≤ high
4. mid calculate
5. condition ke basis pe left ya right move

Must-do questions:

1. Binary Search
2. Search Insert Position
3. First Bad Version
4. Search in Rotated Sorted Array
5. Find Minimum in Rotated Sorted Array
6. Koko Eating Bananas
7. Capacity To Ship Packages Within D Days
8. Median of Two Sorted Arrays, baad mein karna

Binary search ka main hint

Agar question mein “minimum possible maximum”, “maximum possible minimum”, “can we do in X time”, aise words hain, toh binary search on answer ho sakta hai.

Example:

Koko Eating Bananas mein speed find karni hai. Tum speed pe binary search kar sakte ho.

Phase 6: Linked List, slow but important#

Linked List initially irritating lagti hai kyunki pointer handling tricky hoti hai. But once pattern samajh aa gaya, questions repeat type ke hote hain.

Must-do linked list questions

1. Reverse Linked List
2. Merge Two Sorted Lists
3. Linked List Cycle
4. Middle of the Linked List
5. Remove Nth Node From End
6. Reorder List
7. Add Two Numbers
8. Copy List with Random Pointer

Linked List tips

1. Dummy node use karna seekho
2. Slow-fast pointer pattern samjho
3. Null checks carefully karo
4. Diagram banao before coding
5. Pehle paper pe pointer movement dry run karo

Agar tum Java ya C++ use kar rahe ho, null pointer errors common hain. Ghabrao mat, ye process ka part hai.

Phase 7: Trees, interviews ka favourite topic#

Trees product companies mein bahut pooche jaate hain. Razorpay, PhonePe, Swiggy type companies ke interviews mein tree traversal, recursion, BFS, DFS ka strong hona important hai.

Tree basics

1. Root
2. Left child
3. Right child
4. Leaf node
5. Height
6. Depth
7. Balanced tree
8. Binary Search Tree

Must-do tree questions

1. Maximum Depth of Binary Tree
2. Invert Binary Tree
3. Same Tree
4. Subtree of Another Tree
5. Binary Tree Level Order Traversal
6. Validate Binary Search Tree
7. Lowest Common Ancestor
8. Diameter of Binary Tree
9. Path Sum
10. Kth Smallest Element in BST

DFS vs BFS

DFS matlab depth mein jao, recursion ya stack se.

BFS matlab level by level jao, queue se.

Agar question mein “level order”, “minimum depth”, “nearest” type words hain, BFS try karo. Agar “path”, “height”, “subtree”, “ancestor” type words hain, DFS useful hota hai.

Phase 8: Graphs, डर मत, pattern pakad#

Graph ka naam sunte hi beginners ko lagta hai “ye advanced hai”. Actually basic graph questions manageable hain, agar BFS DFS clear hai.

Graph basics

1. Nodes
2. Edges
3. Directed graph
4. Undirected graph
5. Weighted graph
6. Adjacency list
7. Visited set
8. Connected components

Must-do graph questions

1. Number of Islands
2. Clone Graph
3. Max Area of Island
4. Course Schedule
5. Pacific Atlantic Water Flow
6. Rotting Oranges
7. Word Ladder
8. Network Delay Time
9. Min Cost to Connect All Points
10. Redundant Connection

Graph approach

1. Input ko graph mein convert karo
2. Visited structure banao
3. BFS ya DFS choose karo
4. Component count, path, cycle, ya shortest distance identify karo
5. Edge cases handle karo

Graph questions mein sabse common mistake visited mark late karna hota hai. Usually node ko queue mein add karte hi visited mark kar do.

Phase 9: Dynamic Programming, DP ko monster mat banao#

DP ka naam sunke log seedha give up kar dete hain. But DP bhi pattern-based hai. Tumhe bas repeated subproblem aur optimal substructure identify karna hai.

Simple language mein: Agar same calculation baar-baar ho rahi hai, result store kar lo.

DP ke types

1. 1D DP
2. 2D DP
3. Knapsack style
4. Subsequence DP
5. Grid DP
6. Interval DP, later stage ke liye

Beginner DP questions

1. Climbing Stairs
2. House Robber
3. Min Cost Climbing Stairs
4. Coin Change
5. Longest Increasing Subsequence
6. Longest Common Subsequence
7. Unique Paths
8. Decode Ways
9. Partition Equal Subset Sum
10. Word Break

DP solve karne ka method

1. Recursion relation socho
2. Base case define karo
3. Memoization lagao
4. Tabulation mein convert karo, agar zarurat ho
5. Space optimize baad mein karo

DP mein 20 questions tak confusion normal hai. 40 questions ke baad patterns visible hone lagte hain. 70 questions ke baad confidence aata hai.

Daily LeetCode routine for beginners#

Agar tum college student ho ya job ke saath prepare kar rahe ho, routine realistic hona chahiye. 8 ghante daily ka plan bana ke 3 din mein quit karne se better hai 90 minutes daily consistency.

90-minute daily plan

1. 10 min: Previous question revise
2. 20 min: New problem read and think
3. 25 min: Brute force code
4. 20 min: Optimized approach learn
5. 10 min: Notes banao
6. 5 min: Mistake log update karo

Weekend plan

Saturday:

1. 3 old questions revise
2. 2 medium questions solve
3. Ek topic ka summary note banao

Sunday:

1. Mock contest do
2. Wrong questions analyze karo
3. Next week ka topic plan karo

LeetCode pe question solve karte time exact process#

Yeh process follow karna. Randomly code mat likhna.

Step 1: Problem ko apni language mein rewrite karo

Example:

“Given an array, find max sum of contiguous subarray.”

Isko likho:

“Mujhe continuous elements ka group chahiye jiska sum maximum ho.”

Jab problem apni language mein samajh aati hai, solution easier hota hai.

Step 2: Constraints check karo

Constraints se pata chalta hai brute chalega ya nahi.

Example:

• n ≤ 100, O(n²) chal sakta hai
• n ≤ 10⁵, O(n log n) ya O(n) chahiye
• n ≤ 10⁶, mostly O(n)
• Strings length huge hai, nested loops avoid karo

Step 3: Brute force first

Beginner ko brute force ignore nahi karna chahiye. Brute force se logic clear hota hai.

Interviewer bhi dekhta hai ki tum problem tod sakte ho ya nahi. Direct optimized answer bolna zaruri nahi, thinking journey important hai.

Step 4: Optimize using pattern

Ask yourself:

1. Kya hash map use ho sakta hai?
2. Kya sorting se simple hoga?
3. Kya two pointer possible hai?
4. Kya window maintain karni hai?
5. Kya recursion tree repeat ho raha hai?
6. Kya BFS shortest path dega?
7. Kya binary search answer pe ho sakta hai?

Step 5: Dry run before submit

LeetCode submit button tempting hota hai. But pehle dry run karo.

Test cases:

1. Empty input
2. Single element
3. All same values
4. Negative values
5. Already sorted
6. Reverse sorted
7. Large values
8. Duplicate values

Notes banana zaruri hai, warna sab bhool jaoge#

LeetCode ka biggest trap hai: aaj solution samjha, kal bhool gaye.

Isliye ek simple Google Doc, Notion, ya notebook banao.

Har question ke liye note format

1. Question name
2. Topic
3. Pattern
4. Brute force idea
5. Optimized idea
6. Time complexity
7. Space complexity
8. Mistake I made
9. Key trick
10. Revisit date

Example:

Question: Longest Substring Without Repeating Characters
Pattern: Sliding Window + Hash Set
Mistake: Left pointer update properly nahi kiya
Key trick: Duplicate milte hi left ko move karo until duplicate remove ho

Ye notes interview se 2 week pehle gold ban jaate hain.

30-day beginner LeetCode plan#

Agar tum bilkul beginner ho, yeh 30-day plan follow karo.

Week 1: Basics + Arrays

Day 1: Language setup, loops, arrays
Day 2: Two Sum, Contains Duplicate
Day 3: Best Time to Buy and Sell Stock
Day 4: Maximum Subarray
Day 5: Product of Array Except Self
Day 6: Group Anagrams
Day 7: Revision + 2 old questions

Week 2: Two Pointers + Sliding Window

Day 8: Valid Palindrome, Two Sum II
Day 9: 3Sum
Day 10: Container With Most Water
Day 11: Longest Substring Without Repeating Characters
Day 12: Longest Repeating Character Replacement
Day 13: Permutation in String
Day 14: Revision + mock

Week 3: Stack + Binary Search + Linked List

Day 15: Valid Parentheses, Min Stack
Day 16: Daily Temperatures
Day 17: Binary Search, Search Insert Position
Day 18: Search in Rotated Sorted Array
Day 19: Reverse Linked List
Day 20: Linked List Cycle, Merge Two Lists
Day 21: Revision

Week 4: Trees + Graphs + DP intro

Day 22: Maximum Depth, Invert Tree
Day 23: Level Order Traversal
Day 24: Validate BST
Day 25: Number of Islands
Day 26: Rotting Oranges
Day 27: Climbing Stairs, House Robber
Day 28: Coin Change
Day 29: Full revision
Day 30: Mock interview style practice

30 days mein tum expert nahi banoge, but beginner se confident problem solver ban jaoge.

3-month roadmap for placement and internships#

Agar tum serious ho and target hai ₹8 LPA se ₹25 LPA roles, 3 months ka plan better hai.

Month 1: Foundation

Target: 80 questions

1. Arrays: 20
2. Hashing: 15
3. Two pointers: 10
4. Sliding window: 10
5. Stack: 10
6. Binary search: 10
7. Revision: 5

Month 2: Core interview topics

Target: 90 questions

1. Linked List: 15
2. Trees: 25
3. Graphs: 20
4. Heap: 10
5. Backtracking: 10
6. Mixed medium: 10

Month 3: DP + mocks + company prep

Target: 80 questions

1. DP: 30
2. Graph advanced: 10
3. Binary search on answer: 10
4. Company tagged questions: 15
5. Mock interviews: 10
6. Revision: 5

Total: Around 250 questions.

Agar yeh properly kar liya, toh TCS Digital, Infosys SP, Wipro Turbo, Zoho, Accenture Advanced role, aur mid-level product company internships ke liye strong base ban jaayega.

Company-wise LeetCode prep kaise kare#

Service companies: TCS, Infosys, Wipro

Yahan mostly basics, aptitude, coding easy-medium level hota hai.

Focus topics:

1. Arrays
2. Strings
3. Hashing
4. Sorting
5. Basic recursion
6. Basic DP
7. Math

Expected coding level: Easy to lower medium
Salary range: ₹3.5 LPA se ₹9.5 LPA

Product startups: Razorpay, Paytm, PhonePe

Yahan DSA medium strong chahiye. System design fresher ke liye light ho sakta hai, but problem solving solid honi chahiye.

Focus topics:

1. Arrays and hashing
2. Sliding window
3. Binary search
4. Trees
5. Graphs
6. DP
7. Heap

Expected level: Medium to few hard
Salary range: ₹12 LPA se ₹30 LPA

Food tech: Swiggy, Zomato

In companies mein interviews role ke hisaab se vary karte hain. SDE roles ke liye DSA, projects, backend basics, DBMS, OS important hain.

Focus topics:

1. Medium DSA
2. API projects
3. SQL
4. Low-level design basics
5. Problem solving communication

Salary range: ₹15 LPA se ₹35 LPA, role aur college ke hisaab se.

Common mistakes jo beginners karte hain#

1. Solution dekh ke “samajh gaya” bolna

Samajhna aur khud likhna alag cheez hai. Solution dekhne ke baad 24 hours later khud code likho.

2. Random questions solve karna

Pattern-wise solve karo. Pehle arrays ke 15 questions, phir sliding window, phir binary search.

3. Revision skip karna

DSA memory game nahi hai, but patterns retain karne ke liye revision zaruri hai.

4. Time complexity ignore karna

Interview mein sirf code nahi, complexity bhi puchenge. Har solution ke baad bolo:

• Time: O(n)
• Space: O(n)

5. Discussion section mein kho jaana

LeetCode discussion helpful hai, but beginner ke liye overwhelming bhi. Pehle apna attempt do, phir editorial ya top solution dekho.

6. Hard questions se ego battle

Hard question nahi ho raha toh tum dumb nahi ho. Bas abhi pattern ready nahi hai. Wapas medium pe aao.

7. Sirf LeetCode, resume zero

Bhai DSA important hai, but resume bhi important hai. Agar resume ATS mein reject ho gaya, coding round tak pahunchoge hi nahi.

Interview mein LeetCode solution kaise explain kare#

Coding interview mein silent coding mat karo. Interviewer ko tumhari thinking sunni hoti hai.

Answer structure

1. “Main pehle brute force approach explain karta hoon.”
2. “Iska time O(n²) hoga.”
3. “Ab optimize kar sakte hain using hash map.”
4. “Hash map mein previous values store karenge.”
5. “Har step pe complement check karenge.”
6. “Final time O(n), space O(n).”
7. “Edge cases: empty array, duplicates, negative numbers.”

Ye approach tumhe professional dikhata hai. Even if code thoda imperfect ho, thinking strong dikhegi.

Contest dena chahiye kya?#

Haan, but beginner first month mein contest se zyada pressure mat lo. LeetCode Weekly Contest helpful hai speed ke liye.

Contest ka benefit

1. Time pressure handle karna
2. New patterns dekhna
3. Rank compare karke reality check
4. Fast debugging improve karna
5. Confidence build karna

Start mein 4 questions mein se 1 solve hua toh bhi good. Dheere-dheere 2 solve honge, phir 3.

Kitne LeetCode questions enough hain?#

Ye common doubt hai. Exact number magic nahi hai, but practical benchmark yeh hai:

For service company placements

100 to 150 good questions enough ho sakte hain.

Focus:

1. Easy: 80
2. Medium: 50
3. Hard: optional

For product company internships

200 to 300 questions solid chahiye.

Focus:

1. Easy: 80
2. Medium: 180
3. Hard: 20

For top product SDE roles

350+ questions, plus strong CS fundamentals, projects, mock interviews.

Focus:

1. Easy: 100
2. Medium: 220
3. Hard: 50

But yaad rakho, 500 copied solutions se better 200 genuinely solved questions.

LeetCode ke saath kya aur karna chahiye?#

Sirf LeetCode se job nahi milti. Job ke liye full package chahiye.

Saath mein ye bhi karo

1. Resume ATS-friendly banao
2. LinkedIn profile clean rakho
3. 2 solid projects banao
4. GitHub pe code push karo
5. SQL basics karo
6. DBMS, OS, CN revise karo
7. Mock interviews do
8. Referrals ke liye message template ready rakho

Agar tum fresher ho, ek good resume + DSA + 2 projects = interviews ke chances kaafi improve.

Final advice: Consistency beats motivation#

Motivation aaj hai, kal nahi. System daily hona chahiye.

Agar tu roz 2 questions solve karta hai, 6 months mein 300+ questions ho jaate hain. Agar tum sirf Sunday ko 10 questions karne ka plan banate ho, mostly nahi hoga.

Start small:

1. Daily 1 easy
2. Fir daily 1 medium
3. Fir alternate day 2 questions
4. Weekly revision
5. Monthly mock

LeetCode ka goal “green tick collect karna” nahi hai. Goal hai interview mein naye problem ko dekh ke panic na karna.

Aur ek last real talk: Coding round clear karne se pehle resume shortlist hona zaruri hai. Agar tumhara resume ATS-friendly nahi hai, keywords missing hain, projects weak dikh rahe hain, toh TCS, Infosys, Wipro se lekar Razorpay, Swiggy, Paytm tak kahin bhi callback miss ho sakta hai.

Apna resume check karna hai ki ATS pass karega ya reject? JobRise ka free ATS checker use karo: Free ATS Resume Checker