From a52f63efd443ec92a53509915bc4d8e69b55a51f Mon Sep 17 00:00:00 2001
From: leo <leo@azuminha.com>
Date: Wed, 14 Feb 2024 16:27:12 -0300
Subject: first

---
 algorithms/quicksort.c        | 46 ++++++++++++++++++++
 data_structures/linked_list.c | 98 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 144 insertions(+)
 create mode 100644 algorithms/quicksort.c
 create mode 100644 data_structures/linked_list.c

diff --git a/algorithms/quicksort.c b/algorithms/quicksort.c
new file mode 100644
index 0000000..a0f0153
--- /dev/null
+++ b/algorithms/quicksort.c
@@ -0,0 +1,46 @@
+#include <stdio.h>
+
+//pior caso \theta(n²)
+//eficiencia media \theta(nlog(n))
+int partition(int *A, int p, int r){
+	//escolher o pivot(vai ser o ultimo, pois fica mais facil de implementar
+	//caso queira escolher um pivo aleatório, basta trocar A[pos_aleatoria] com A[r]
+	int pivot = A[r];
+	int pos_pivot = p;
+	for(int i=p; i < r; ++i){
+		if(A[i] <= pivot){
+			int aux = A[i];
+			A[i] = A[pos_pivot];
+			A[pos_pivot] = aux;
+
+			pos_pivot++;
+		}
+	}
+	int aux = A[pos_pivot];
+	A[pos_pivot] = pivot;
+	A[r] = aux;
+
+	return pos_pivot;
+}
+
+int quicksort(int *A, int p, int r){
+	printf("p: %d, r: %d\n", p, r);
+	if(p < r){
+		int q = partition(A, p, r);
+		quicksort(A, p, q-1);
+		quicksort(A, q+1, r);
+	}
+}
+
+
+int main(){
+	// pp = 0
+	// 13 32 52 69 420 22 42
+	int A[7] = {42, 32, 52, 69, 420, 22, 13};
+	quicksort(A, 0, 6);
+	for(int i=0; i<7; ++i){
+		printf("%d ", A[i]);
+	}
+	printf("\n");
+	return 0;
+}
diff --git a/data_structures/linked_list.c b/data_structures/linked_list.c
new file mode 100644
index 0000000..b75dfea
--- /dev/null
+++ b/data_structures/linked_list.c
@@ -0,0 +1,98 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct Node{
+	int value;
+	struct Node* next;
+}list;
+
+void* create_list(){
+	void* ptr = NULL; 
+	return ptr;
+}
+
+void add_node(list **head, int value){
+	list *node = (list*)malloc(sizeof(list));
+	node->value = value;
+	node->next = NULL;
+	
+	if(*head == NULL){
+		*head = node;
+	}else{
+		list *tmp = *head;
+		while(tmp->next != NULL){
+			tmp = tmp->next;
+		}
+		tmp->next = node;
+	}
+}
+
+void print_list(list *head){
+	while(head != NULL){
+		printf("%d -> ", head->value);
+		head = head->next;
+	}
+	printf("\n");
+}
+
+void remove_first(list **head){
+	list *tmp = *head;
+	*head = (*head)->next;
+	free(tmp);
+}
+
+int list_len(list *head){
+	int cont = 0;
+	while(head != NULL){
+		cont++;
+		head = head->next;
+	}
+	return cont;
+}
+
+void add_node_pos(list **head, int pos, int value){
+	if(pos > list_len(*head)){
+		fprintf(stderr, "Posicao nao existe\n");
+		return;
+	}
+
+	list *new_node = (list*)malloc(sizeof(list));
+	new_node->value = value;
+
+	if(pos == 0){
+		new_node->next = *head;
+		*head = new_node;
+		return;
+	}
+	
+
+	int cont = 0;
+	list *f = *head;
+	list *s = NULL;
+	while(cont != pos){
+		s = f;
+		f = f->next;
+		cont++;
+	}
+	s->next = new_node;
+	new_node->next = f;
+}
+
+int main(int argv, char* argc[]){
+	list *l = create_list();
+	
+	add_node(&l, 10);
+	add_node(&l, 20);
+	add_node(&l, 30);
+	print_list(l);
+	add_node_pos(&l, 3, 50);
+	print_list(l);
+	add_node_pos(&l, 3, 40);
+	print_list(l);
+	add_node_pos(&l, 0, 0);
+	print_list(l);
+	add_node_pos(&l, 1, 5);
+	print_list(l);
+
+	return 0;
+}
-- 
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