From eceb8d69f41b07dffbb37f9b8c98896e0aa000f1 Mon Sep 17 00:00:00 2001
From: Valentin Gehrke <madmaurice@zom.bi>
Date: Thu, 11 Feb 2016 16:39:15 +0100
Subject: [PATCH] EPA: Binary Tree

---
 binarytree.c | 159 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 binarytree.c

diff --git a/binarytree.c b/binarytree.c
new file mode 100644
index 0000000..22818c5
--- /dev/null
+++ b/binarytree.c
@@ -0,0 +1,159 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+typedef struct s_node {
+    int element;
+    struct s_node* left;
+    struct s_node* right;
+} *Nodeptr, Node;
+
+typedef Nodeptr* Tree;
+
+Tree tree_create() {
+    Tree t = malloc(sizeof( Nodeptr ));
+    *t = NULL;
+    return t;
+}
+
+void tree_add(Tree t, int element) {
+    Nodeptr n = malloc(sizeof(Node));
+    n->element = element;
+    n->left = NULL;
+    n->right = NULL;
+
+    if(*t == NULL) {
+        *t = n;
+    } else {
+        Nodeptr iter = *t;
+        while(1) {
+            if(iter->element > element) {
+                if(iter->left == NULL) {
+                    iter->left = n;
+                    return;
+                } else {
+                    iter = iter->left;
+                }
+            } else if(iter->element < element) {
+                if(iter->right == NULL) {
+                    iter->right = n;
+                    return;
+                } else {
+                    iter = iter->right;
+                }
+            } else {
+                free(n);
+                return;
+            }
+        }
+    }
+}
+
+void tree_remove(Tree t, int element) {
+    Nodeptr iter = *t;
+    Nodeptr parent = NULL;
+    while(iter != NULL) {
+        if(iter->element > element) {
+            parent = iter;
+            iter = iter->left;
+        } else if(iter->element < element) {
+            parent = iter;
+            iter = iter->right;
+        } else {
+            break;
+        }
+    }
+    if(iter == NULL) return; // Not found
+
+    if(iter->right == NULL) {
+        if(parent == NULL)              *t = iter->left;
+        else if(parent->left == iter)   parent->left = iter->left;
+        else if(parent->right == iter)  parent->right = iter->left;
+        else assert(0);
+        free(iter);
+    } else if(iter->left == NULL) {
+        if(parent == NULL)              *t = iter->right;
+        else if(parent->left == iter)   parent->left = iter->right;
+        else if(parent->right == iter)  parent->right = iter->right;
+        else assert(0);
+        free(iter);
+    } else {
+        Nodeptr iter2, parent2;
+        iter2 = iter->left;
+        parent2 = NULL;
+        while(iter2->right != NULL) {
+            parent2 = iter2;
+            iter2 = iter2->right;
+        }
+        if(parent2 == NULL) {
+            iter->left = iter2->left;
+        } else {
+            parent2->right = iter2->left;
+        }
+        iter->element = iter2->element;
+        free(iter2);
+    }
+}
+
+int tree_contains(Tree t, int element) {
+    Nodeptr iter = *t;
+    while(iter != NULL) {
+        if(iter->element > element) {
+            iter = iter->left;
+        } else if(iter->element < element) {
+            iter = iter->right;
+        } else {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+void tree_print_node_rec(Nodeptr n, int level) {
+    if(n == NULL) return;
+
+    tree_print_node_rec(n->right,level+1);
+
+    for(int i = 0; i < level; i++) printf("\t");
+    printf("%d\n", n->element);
+
+    tree_print_node_rec(n->left, level+1);
+}
+
+void tree_print(Tree t) {
+    tree_print_node_rec(*t, 0);
+    printf("----------\n");
+}
+
+void tree_nodefree_rec(Nodeptr n) {
+    if(n == NULL) return;
+    tree_nodefree_rec(n->left);
+    tree_nodefree_rec(n->right);
+    free(n);
+}
+
+void tree_free(Tree t) {
+    tree_nodefree_rec(*t);
+    free(t);
+}
+
+int main( int argc, char *argv[] ) {
+	int data[10] = {5,7,2,8,6,4,3,1,9,0};
+    Tree t = tree_create();
+    for(int i = 0; i < 10; i++) {
+        tree_add(t,data[i]);
+    }
+    tree_print(t);
+    for(int i = 0; i < 10; i++) {
+        assert(tree_contains(t,data[i]));
+    }
+    for(int i = 0; i < 5; i++) {
+        tree_remove(t,data[i]);
+    }
+    tree_print(t);
+    for(int i = 5; i < 10; i++) {
+        assert(tree_contains(t,data[i]));
+    }
+    tree_free(t);
+	return 0;
+}