Fenwick / Binary Indexed Tree

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Task

📝 **Question:** Build BIT for n=5 by updating each index with [3,2,-1,6,5]. Query range_sum(2, 4) (=2 + -1 + 6 = 7). Print it.

📋 Pick the right answer.

💡 **Hint:** Re-read the theory above if unsure.

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🎯write

Trie: prefix autocomplete

🎯writeFREE

Two pointers: pair sum

🎯write

Two pointers: palindrome check

🤖predictFREE

Prerequisites — what you should know before this track

⚡predictFREE

Prerequisites — what you should know before this track

✏️ Write your code here

🐍

Loading Python...

First visit only — ~5-10s. Stays cached afterward.

📊 Result

Press Run to see result...

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💬 Discussion