LeetCode 118 | Pascal's Triangle | 2D DP Pattern Explained | C++

LeetCode 118 — Pascal's Triangle. Generate the first numRows
rows of Pascal's Triangle. A fundamental 2D dynamic programming
problem that every beginner must solve — each cell is just the
sum of the two cells above it. Clean, visual, and satisfying.

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🔗 IMPORTANT LINKS

💻 GitHub (Solutions Repo) → https://github.com/hanumanraj07/LeetCode
🌐 Portfolio → https://hanumanrajpurohit.vercel.app
💼 LinkedIn → https://linkedin.com/in/hanumanraj07
🧩 Problem Link → https://leetcode.com/problems/pascals-triangle/

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📌 WHAT IS THIS PROBLEM?

Given numRows, generate the first numRows of Pascal's Triangle
where each interior cell is the sum of the two cells above it.

numRows = 5
Output → [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]

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🛠️ APPROACH COVERED

Method → Row-by-row construction using previous row
Language → C++
Time → O(numRows²)
Space → O(numRows²)

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🎯 WHAT YOU WILL LEARN

→ How each row starts and ends with 1
→ How interior values are built from the previous row
→ Building the triangle iteratively using a 2D vector
→ Connection to binomial coefficients and combinatorics
→ Clean C++ implementation with dry run
→ Connection to LeetCode 119 (Pascal's Triangle II)

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📬 CONNECT WITH ME

💼 LinkedIn → https://linkedin.com/in/hanumanraj07
🌐 Portfolio → https://hanumanrajpurohit.vercel.app
💻 GitHub → https://github.com/hanumanraj07

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Видео LeetCode 118 | Pascal's Triangle | 2D DP Pattern Explained | C++ канала Hanuman Singh Rajpurohit