Source Map — Level 5: Prefix, Difference, Contribution¶
এই folder-এর প্রতিটা concept আর problem-এর উৎসের হিসাব। সব Bengali prose, diagram আর code এই repo-র জন্য নতুন করে লেখা; কোনো বই বা সাইটের লেখার copy বা অনুবাদ নয়। Problem statement কোথাও তুলে আনা হয়নি — শুধু official link দেওয়া আছে।
| Concept / Problem | Source Type | Source Name | Link | How it is used | Copying status |
|---|---|---|---|---|---|
| Prefix sum, range sum formula | Common knowledge | Standard CP curriculum | — | concept-notes.md-র মূল ব্যাখ্যা; ফিতা/মাইলফলক analogy নিজের | original explanation |
| ফিতা, টোল-সাইনবোর্ড, পাখা analogies | This repo | concept-notes.md, visualization-ideas.md | ./concept-notes.md | শেখানোর নিজস্ব framing | original explanation |
| Range Sum Query Immutable | Online judge | LeetCode Range Sum Query Immutable | https://leetcode.com/problems/range-sum-query-immutable/ | Problem 067/068-এর practice link | official link only |
| Static Range Sum Queries | Online judge | CSES Static Range Sum Queries | https://cses.fi/problemset/task/1646 | Problem 067/068-এর CP practice link | official link only |
| Difference array / range update | Educational site | USACO Guide (Silver level technique) | https://usaco.guide/ | Problem 069/070-এর reading reference; ব্যাখ্যা নিজের ভাষায় | official link only |
| Prefix XOR / Range Xor Queries | Online judge | CSES Range Xor Queries | https://cses.fi/problemset/task/1650 | Problem 071-এর practice link; cancel ব্যাখ্যা নিজের | official link only |
| 2D prefix sum | Online judge | LeetCode Range Sum Query 2D Immutable | https://leetcode.com/problems/range-sum-query-2d-immutable/ | Problem 072-এর practice link; ফ্রেম-কাটা ছবি নিজের | official link only |
| Forest Queries (2D prefix) | Online judge | CSES Forest Queries | https://cses.fi/problemset/task/1652 | Problem 072-এর CP practice link | official link only |
| Subarray Sum Equals K | Online judge | LeetCode Subarray Sum Equals K | https://leetcode.com/problems/subarray-sum-equals-k/ | Problem 073-এর practice link; hash map dry run নিজের | official link only |
| Subarray Sums Divisible by K | Online judge | LeetCode Subarray Sums Divisible by K | https://leetcode.com/problems/subarray-sums-divisible-by-k/ | Problem 074-এর practice link; remainder-জোড়া ব্যাখ্যা নিজের | official link only |
| Subarray Divisibility | Online judge | CSES Subarray Divisibility | https://cses.fi/problemset/task/1662 | Problem 074-এর CP practice link | official link only |
| Contribution technique, (i+1)*(n-i) | Common knowledge | Classic CP technique | — | Problem 075/076/078; বাঁ-ডান পছন্দের ছবি নিজের | original explanation |
| Sum of Subarray Minimums | Online judge | LeetCode Sum of Subarray Minimums | https://leetcode.com/problems/sum-of-subarray-minimums/ | Problem 077-এর practice link; span ব্যাখ্যা নিজের | official link only |
| Imos method, sweep line | Common knowledge | Classic CP techniques | — | Problem 079/080; দরজার কাউন্টার analogy নিজের | original explanation |
| Problem note template | This repo | math-problem-note-template.md | ../../templates/math-problem-note-template.md | problems/README.md থেকে রেফার করা | original explanation |
| Hash map deep dive forward link | This repo | Hashing folder | ../../05-hashing/ | 073 থেকে cross-reference | original explanation |
| Monotonic stack forward link | This repo | Stack and Queue folder | ../../04-stack-and-queue/ | 077 থেকে cross-reference | original explanation |