Assignment 2

Assignment 2 clang-format

Assignment 2 more comment

Assignment 2 correct comment

assignment2/BST.c

@@ -0,0 +1,118 @@
+/*
+ * Author: Walter
+ * Student ID: 1930006025
+ * programming_assignment_2
+ */
+
+#include "BST.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+Node *insertNode(Node **proot, int x) {
+	Node **tmpNode;
+
+	/* find the position needs to be insert */
+	tmpNode = proot;
+	while (*tmpNode) {
+		if (x < (*tmpNode)->key) {
+			tmpNode = &(*tmpNode)->left;
+		} else if (x > (*tmpNode)->key) {
+			tmpNode = &(*tmpNode)->right;
+		} else {
+			/* same key exists */
+			return NULL;
+		}
+	}
+
+	/* create node */
+	*tmpNode = (Node *)malloc(sizeof(Node));
+	if (tmpNode == NULL) {
+		fprintf(stderr, "Can not allocate new space for node\n");
+		exit(1);
+	}
+
+	/* copy value */
+	(*tmpNode)->key = x;
+	(*tmpNode)->left = (*tmpNode)->right = NULL;
+
+	return *tmpNode;
+}
+
+Node *findNode(Node *root, int x) {
+	while (root) {
+		/* find in children */
+		if (x < root->key) {
+			root = root->left;
+		} else if (x > root->key) {
+			root = root->right;
+		} else {
+			/* equal */
+			return root;
+		}
+	}
+
+	/* not found */
+	return NULL;
+}
+
+Node *deleteNode(Node **proot, int x) {
+	Node **rMin, **delNode, *freeNode;
+
+	/* find the node needs to be delete */
+	delNode = proot;
+	while (*delNode) {
+		if (x < (*delNode)->key) {
+			delNode = &(*delNode)->left;
+		} else if (x > (*delNode)->key) {
+			delNode = &(*delNode)->right;
+		} else {
+			/* found */
+			break;
+		}
+	}
+	/* check not found */
+	if (!(*delNode)) {
+		return NULL;
+	}
+
+	if ((*delNode)->left && (*delNode)->right) {
+		/* two children, find the right min and replace */
+		rMin = &((*delNode)->right);
+		while ((*rMin)->left) {
+			rMin = &(*rMin)->left;
+		}
+
+		/* replace */
+		(*delNode)->key = (*rMin)->key;
+
+		/* now let's delete rMin */
+		delNode = rMin;
+	}
+
+	/* delete delNode, freeNode is the one needs to be free */
+	freeNode = *delNode;
+	if ((*delNode)->left || (*delNode)->right) {
+		/* one child, freeNode is the one needs to be free */
+		if ((*delNode)->left) {
+			*delNode = (*delNode)->left;
+		} else if ((*delNode)->right) {
+			*delNode = (*delNode)->right;
+		}
+	} else {
+		/* no child */
+		*delNode = NULL;
+	}
+
+	return freeNode;
+}
+
+void destroyTree(Node *root) {
+	/* end situation */
+	if (root == NULL) {
+		return;
+	}
+	destroyTree(root->left);
+	destroyTree(root->right);
+	free(root);
+	return;
+}