06. Hashing & Strings

🧠 Strategy: Hashing & Strings

1. Frequency Map: Use HashMap<Character, Integer> for anagrams or counting chars.
2. Subarray Sum: Use a map to store (cumulativeSum, index). If sum - k exists in map, you found a subarray.
3. Sliding Window: Use a Map to track counts inside the current window [L, R].
4. Pattern Matching: For standard patterns, use KMP (LPS array) or Z-Algorithm.

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🟢 Basic Strings

• Reverse The String
• Simple Reverse
• Toggle Case
• Palindrome String
• Largest Palindrome
• Length Of Last Word
• Count A

🟡 Hashing: Arrays & Zero Sums

• Subarray With Zero Sum
• Largest Continuous Sequence Zero Sum
• Subarray Sum Equals K
• Subarray With Given Sum
• Diffk II
• First Repeating Element
• Common Elements
• Check Palindrome II
• Find Pairs Sum Present
• Pairs With Given Xor

🟠 Hashing: Windows & Sequences

• Longest Consecutive Sequence
• Distinct Numbers In Window
• Window String
• Longest Substring Without Repeat
• Permutations Of A In B
• Shaggy And Distances
• Is Dictionary
• Valid Sudoku
• Colorful Number
• Sort Array In Given Order
• Compare Sorted Subarrays

🔴 Advanced Pattern Matching

• Cyclic Permutations
• Period Of A String
• Smallest Prefix String
• Closest Palindrome
• Make String Palindrome
• Boring Substring
• Replicating Substring

🟣 Hashing: Geometry

• Points On Same Line
• Count Rectangles
• Count Right Triangles
• Unique 2D Points

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