upd

org/cpp/containers.org

@@ -0,0 +1,109 @@
+#+title: C++ Containers
+
+* Container Concept: Common Interface :containers:concept:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504002
+:END:
+** Front
+What interface is shared by all C++ standard containers?
+** Back
+- *Element access*: ~at~, ~operator[]~, ~front~, ~back~, ~data~
+- *Iterators*: ~begin~, ~end~, ~cbegin~, ~cend~, ~rbegin~, ~rend~
+- *Capacity*: ~empty~, ~size~, ~max_size~
+- *Modifiers*: ~clear~, ~insert~, ~erase~, ~push_back~, ~pop_back~, ~resize~, ~swap~
+
+* Do C++ containers inherit from a common base? :containers:concept:inheritance:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504003
+:END:
+** Front
+Do C++ containers (vector, list, map, etc.) inherit from a common base class?
+** Back
+No. Standard containers are standalone classes. Shared interfaces come from conventions and C++20 concepts (~Container~, ~SequenceContainer~), not inheritance.
+
+* Sequence Containers :containers:sequence:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504004
+:END:
+** Front
+What are the C++ sequence containers?
+** Back
+~vector~, ~deque~, ~list~, ~forward_list~, ~array~
+
+Sequence containers maintain insertion order.
+
+* Associative Containers :containers:associative:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504005
+:END:
+** Front
+What are the C++ associative containers?
+** Back
+- *Ordered*: ~set~, ~multiset~, ~map~, ~multimap~
+- *Unordered*: ~unordered_set~, ~unordered_multiset~, ~unordered_map~, ~unordered_multimap~
+
+* Container Adapters :containers:adapter:
+:PROPERTIES:
+:ANKI_NOTE_ID: 1777826871054
+:END:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504006
+** Front
+What are the C++ container adapters?
+** Back
+~stack~, ~queue~, ~priority_queue~
+
+Adapters provide a restricted interface (e.g., LIFO for stack, FIFO for queue).
+
+* What does vector have that other containers don't? :containers:vector:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504007
+:END:
+** Front
+Which methods does ~vector~ have that other containers typically don't?
+** Back
+~reserve~, ~capacity~, ~shrink_to_fit~
+
+These manage the internal memory buffer.
+
+* Unique methods on sequence containers (list, deque) :containers:sequence:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504008
+:END:
+** Front
+Which sequence containers support ~push_front~ and ~pop_front~?
+** Back
+~deque~ and ~list~ (not ~vector~)
+
+These containers support insertion/removal at both ends.
+
+* Unique methods on associative containers :containers:associative:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504009
+:END:
+** Front
+What tree-based methods do ordered associative containers have?
+** Back
+~find~, ~count~, ~lower_bound~, ~upper_bound~, ~equal_range~
+
+These use tree traversal (BST behind the scenes).
+
+* Unique methods on unordered containers :containers:unordered:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504010
+:END:
+** Front
+What hash-specific methods do unordered containers have?
+** Back
+~bucket_count~, ~load_factor~, ~max_load_factor~, ~rehash~, ~reserve~
+
+These manage hash table internals.

org/cpp/deque.org

@@ -1,6 +1,7 @@
 * Task: construct an empty deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650432
 :END:
 ** Front
 Write how to create an empty deque of ints
@@ -12,6 +13,7 @@ std::deque<int> d;
 * Task: construct deque with 5 copies of value :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650427
 :END:
 ** Front
 Write how to create a deque with 5 elements, all initialized to 42
@@ -23,6 +25,7 @@ std::deque<int> d(5, 42);  // {42, 42, 42, 42, 42}
 * Task: construct deque from initializer list :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650422
 :END:
 ** Front
 Write how to create a deque initialized with {1, 2, 3}
@@ -34,6 +37,7 @@ std::deque<int> d = {1, 2, 3};
 * Task: construct deque from a range :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650418
 :END:
 ** Front
 Write how to create a deque from a vector's begin/end iterators
@@ -46,6 +50,7 @@ std::deque<int> d(v.begin(), v.end());
 * Task: access element at index with bounds checking :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650414
 :END:
 ** Front
 Write how to safely access element at index 2 in a deque (throws on invalid index)
@@ -58,6 +63,7 @@ int x = d.at(2);  // returns 30, throws std::out_of_range if invalid
 * Task: access element at index with operator[] :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650409
 :END:
 ** Front
 Write how to access element at index 1 using operator[]
@@ -70,6 +76,7 @@ int x = d[1];  // returns 20, no bounds check
 * Task: access first and last elements :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650404
 :END:
 ** Front
 Write how to get the first and last element of a deque
@@ -83,6 +90,7 @@ int last = d.back();    // 30
 * Task: iterate over deque with begin/end :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650399
 :END:
 ** Front
 Write a range-based for loop over a deque using iterators
@@ -99,6 +107,7 @@ for (int x : d) { std::cout << x << " "; }
 * Task: reverse iterate over deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650395
 :END:
 ** Front
 Write how to iterate backwards through a deque using reverse iterators
@@ -113,6 +122,7 @@ for (auto it = d.rbegin(); it != d.rend(); ++it) {
 * Task: check if deque is empty :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650391
 :END:
 ** Front
 Write how to check if a deque is empty
@@ -125,6 +135,7 @@ if (d.empty()) { /* ... */ }
 * Task: get size of deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650387
 :END:
 ** Front
 Write how to get the number of elements in a deque
@@ -137,6 +148,7 @@ std::size_t n = d.size();  // returns 3
 * Task: clear all elements from deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650383
 :END:
 ** Front
 Write how to remove all elements from a deque
@@ -149,6 +161,7 @@ d.clear();  // size becomes 0
 * Task: push elements to back of deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650379
 :END:
 ** Front
 Write how to add elements 10, 20, 30 to the back of a deque
@@ -163,6 +176,7 @@ d.push_back(30);
 * Task: push elements to front of deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650375
 :END:
 ** Front
 Write how to add elements 30, 20, 10 to the front of a deque (pushing in that order)
@@ -177,6 +191,7 @@ d.push_front(10);  // {10, 20, 30}
 * Task: pop elements from back of deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650371
 :END:
 ** Front
 Write how to remove the last element from a deque
@@ -189,6 +204,7 @@ d.pop_back();  // {1, 2}
 * Task: pop elements from front of deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650367
 :END:
 ** Front
 Write how to remove the first element from a deque
@@ -201,6 +217,7 @@ d.pop_front();  // {2, 3}
 * Task: emplace back into deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650363
 :END:
 ** Front
 Write how to construct a pair in-place at the back of a deque (without copying)
@@ -213,6 +230,7 @@ d.emplace_back(1, 2);  // constructs pair{1,2} directly
 * Task: emplace front into deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650359
 :END:
 ** Front
 Write how to construct an element in-place at the front of a deque
@@ -225,6 +243,7 @@ d.emplace_front("hello");  // constructs string directly at front
 * Task: resize deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650354
 :END:
 ** Front
 Write how to resize a deque to 10 elements, filling new spots with 0
@@ -238,6 +257,7 @@ d.resize(5, 42);     // resize to 5, filling with 42 if growing
 * Task: insert element at position :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650349
 :END:
 ** Front
 Write how to insert value 99 at the beginning of a deque
@@ -250,6 +270,7 @@ d.insert(d.begin(), 99);  // {99, 1, 2, 3}
 * Task: insert multiple copies :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650344
 :END:
 ** Front
 Write how to insert 5 copies of value 42 starting at position begin
@@ -262,6 +283,7 @@ d.insert(d.begin(), 5, 42);  // {42, 42, 42, 42, 42, 1, 2, 3}
 * Task: insert range into deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650339
 :END:
 ** Front
 Write how to insert all elements from a vector into a deque at position begin
@@ -275,6 +297,7 @@ d.insert(d.begin(), v.begin(), v.end());  // {10, 20, 1, 2, 3}
 * Task: erase single element :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650335
 :END:
 ** Front
 Write how to erase the element at position begin + 1 in a deque
@@ -287,6 +310,7 @@ d.erase(d.begin() + 1);  // {1, 3}
 * Task: erase range of elements :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650331
 :END:
 ** Front
 Write how to erase elements from begin to begin+2 (2 elements) in a deque
@@ -299,6 +323,7 @@ d.erase(d.begin(), d.begin() + 2);  // {3, 4, 5}
 * Task: swap two deques :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650326
 :END:
 ** Front
 Write how to swap the contents of two deques
@@ -312,6 +337,7 @@ d1.swap(d2);  // d1 = {4,5,6}, d2 = {1,2,3}
 * Task: emplace at specific position :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650322
 :END:
 ** Front
 Write how to construct a pair in-place at position begin of a deque
@@ -324,6 +350,7 @@ d.emplace(d.begin(), 1, 2);  // constructs pair{1,2} at begin
 * Task: assign new contents to deque :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650318
 :END:
 ** Front
 Write how to replace all contents of a deque with 5 copies of 99
@@ -336,6 +363,7 @@ d.assign(5, 99);  // {99, 99, 99, 99, 99}
 * Task: assign from range :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650314
 :END:
 ** Front
 Write how to replace deque contents with all elements from a vector
@@ -349,6 +377,7 @@ d.assign(v.begin(), v.end());  // {10, 20, 30}
 * Task: use deque as FIFO queue :cpp:deque:production:
 :PROPERTIES:
 :ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 1777825650305
 :END:
 ** Front
 Write how to use deque as a FIFO queue (enqueue 1, 2, 3 then dequeue all)
@@ -364,4 +393,4 @@ while (!q.empty()) {
     q.pop_front();  // dequeue
 }
 // Output: 1 2 3
-#+end_src
+#+end_src

org/cpp/iterator.org

@@ -44,6 +44,9 @@ What are the four required operations for a C++ iterator?
 ** Front
 List the five iterator categories in C++ (from simplest to most advanced)
 ** Back
+:PROPERTIES:
+:ANKI_NOTE_ID: 1777826854918
+:END:
 1. Input Iterator — read values, advance once
 2. Output Iterator — write values, advance once
 3. Forward Iterator — read/write, multiple passes

org/cpp/tricks/tricks.org

@@ -0,0 +1,17 @@
+#+title: C++ Tricks
+
+* Rotate String Check :string:trick:search:
+:PROPERTIES:
+:ANKI_NOTE_TYPE: Basic
+:ANKI_NOTE_ID: 20260504001
+:END:
+** Front
+How to check if string ~s~ can be rotated to match string ~goal~ in O(n)?
+** Back
+#+begin_src c++
+bool rotateString(string s, string goal) {
+    return s.size() == goal.size() && (s + s).find(goal) != string::npos;
+}
+#+end_src
+
+If ~goal~ is a substring of ~s + s~, then ~s~ can be rotated to match ~goal~.