From 8fc59db9baff94a026fa6e38cfd842f3a2556f37 Mon Sep 17 00:00:00 2001
From: Joseph Ferano <joseph@ferano.io>
Date: Wed, 4 Jan 2023 21:09:59 +0700
Subject: [PATCH] First commit with some working examples already

---
 GrokkingAlgorithms.org       |  5 +++
 TheAlgorithmDesignManual.org |  5 +++
 binary_search.org            | 15 ++++++++
 selection_sort.org           | 51 ++++++++++++++++++++++++++++
 stack.org                    | 66 ++++++++++++++++++++++++++++++++++++
 5 files changed, 142 insertions(+)
 create mode 100644 GrokkingAlgorithms.org
 create mode 100644 TheAlgorithmDesignManual.org
 create mode 100644 binary_search.org
 create mode 100644 selection_sort.org
 create mode 100644 stack.org

diff --git a/GrokkingAlgorithms.org b/GrokkingAlgorithms.org
new file mode 100644
index 0000000..826f457
--- /dev/null
+++ b/GrokkingAlgorithms.org
@@ -0,0 +1,5 @@
+#+TITLE: Notes & Exercises: Grokking Algorithms
+#+AUTHOR: Joseph Ferano
+
+** Notes
+** Exercises
diff --git a/TheAlgorithmDesignManual.org b/TheAlgorithmDesignManual.org
new file mode 100644
index 0000000..cd9e0e0
--- /dev/null
+++ b/TheAlgorithmDesignManual.org
@@ -0,0 +1,5 @@
+#+TITLE: Notes & Exercises: The Algorith Design Manual
+#+AUTHOR: Joseph Ferano
+
+** Notes
+** Exercises
diff --git a/binary_search.org b/binary_search.org
new file mode 100644
index 0000000..2996f1f
--- /dev/null
+++ b/binary_search.org
@@ -0,0 +1,15 @@
+
+** OCaml
+
+#+begin_src ocaml
+let binary_search items target =
+  let rec f low high =
+    match (high - low) / 2 + low with
+    | mid when target = items.(mid) -> Some items.(mid)
+    | mid when target < items.(mid) -> f low mid
+    | mid when target > items.(mid) -> f mid high
+    | _ -> None
+  in f 0 (Array.length items);;
+
+binary_search [|1;2;3;4;5|] 3;;
+#+end_src
diff --git a/selection_sort.org b/selection_sort.org
new file mode 100644
index 0000000..05d76fa
--- /dev/null
+++ b/selection_sort.org
@@ -0,0 +1,51 @@
+#+OPTIONS: ^:{}
+
+** Selection Sort
+
+Runtime O(n^{2})
+
+*** Python
+
+#+begin_src python
+def selection_sort(arr):
+    sorted_list = []
+    for i in range(len(arr)):
+        max = arr[0]
+        for count, value in enumerate(arr):
+            if value > max:
+                max = value
+        sorted_list.append(max)
+        arr.remove(max)
+    return sorted_list
+
+selection_sort([2,1,5,3,4])
+#+end_src
+
+*** OCaml
+
+Really reinventing the wheel on this one...
+
+#+begin_src ocaml
+let max_element = function
+  | [] -> invalid_arg "empty list"
+  | x::xs ->
+     let rec f acc = function
+       | [] -> acc
+       | x::xs -> f (if x > acc then x else acc) xs
+     in f x xs
+
+let remove item list = 
+  let rec f acc item = function
+    | [] -> List.rev acc
+    | x::xs -> if item = x then (List.rev acc) @ xs else f (x::acc) item xs
+  in f [] item list
+
+let selection_sort list =
+  let rec f acc = function
+    | [] -> acc
+    | xs ->
+       let m = max xs
+       in f (m::acc) (remove m xs)
+  in f [] list
+#+end_src
+
diff --git a/stack.org b/stack.org
new file mode 100644
index 0000000..d39b1f4
--- /dev/null
+++ b/stack.org
@@ -0,0 +1,66 @@
+** C
+
+#+begin_src C :includes stdlib.h stdio.h stdbool.h
+typedef struct Node {
+    struct Node* next;
+    /* void *data; */
+    int data;
+} Node;
+
+typedef struct Stack {
+    Node* top;
+    int length;
+} Stack;
+
+/* void stack_create(void* data) { */
+Stack *stack_create(int data) {
+    Stack *stack = malloc(sizeof(Stack));
+    Node *node = malloc(sizeof(Node));
+    node->data = data;
+    node->next = NULL;
+    stack->top = node;
+    stack->length = 1;
+    return stack;
+}
+
+int stack_pop(Stack *stack) {
+    Node *top = stack->top;
+    Node *next = top->next;
+    if (stack->length > 0 && next != NULL) {
+        stack->top = next;
+        stack->length--;
+        int value = top->data;
+        free(top);
+        return value;
+    } else {
+        // A better API design would be to return a bool and the int as a pointer
+        // Although once we switch away from int and use void pointers, might not be needed
+        return -1;
+    }
+}
+
+/* void stack_push(Stack *stack, void *data) { */
+void stack_push(Stack *stack, int data) {
+    Node *node = malloc(sizeof(Node));
+    Node *top = stack->top;
+    node->data = data;
+    node->next = top;
+    stack->top = node;
+    stack->length++;
+}
+
+/* void* stack_peak(Stack *stack) { */
+int stack_peak(Stack *stack) {
+    return stack->top->data;
+}
+
+void stack_print(Stack *stack) {
+    Node *current = stack->top;
+    int i = 0;
+    while (current != NULL) {
+        printf("Stack at %d: %d\n", ++i, current->data);
+        current = current->next;
+    }
+    printf("------------------\n");
+}
+#+end_src