Objective-C??BinarySearchTreeNode???

??????????????Binary Search Tree?BST?????????Objective-C?????????????????????

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?????????BinarySearchTreeNode????????????????????????

@interface BinarySearchTreeNode : NSObject@property (nonatomic, assign) NSInteger value;@end

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- (BinarySearchTreeNode *)insert:(NSInteger)newValue afterNode:(BinarySearchTreeNode *)node {    // ?????    BinarySearchTreeNode *newNode = [[BinarySearchTreeNode alloc] init];    newNode.value = newValue;        // ??????    if (node.value < newValue) {        // ?????        if (node.right == nil) {            node.right = newNode;        } else {            // ???????????            BinarySearchTreeNode *rightNode = node.right;            if (rightNode.value < newValue) {                rightNode.right = newNode;            } else {                rightNode.left = newNode;            }        }    } else {        // ?????        if (node.left == nil) {            node.left = newNode;        } else {            // ???????????????            BinarySearchTreeNode *leftNode = node.left;            if (leftNode.value > newValue) {                leftNode.right = newNode;            } else {                leftNode.left = newNode;            }        }    }        return newNode;}

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- (BinarySearchTreeNode *)search:(NSInteger)searchValue {    // ????????    BinarySearchTreeNode *node = [self.root left];        // ????????????    if (node.value == searchValue) {        return node;    }        // ?????????????????????    if (node.value > searchValue) {        if (node.left) {            return [self search:searchValue fromNode:node.left];        } else {            return nil;        }    }        // ?????????????????????    if (node.right) {        return [self search:searchValue fromNode:node.right];    } else {        return nil;    }}- (BinarySearchTreeNode *search:(NSInteger)searchValue fromNode:(BinarySearchTreeNode *)node {    // ????????????    if (node.value == searchValue) {        return node;    }        // ?????????????????????    if (node.value > searchValue) {        if (node.left) {            return [self search:searchValue fromNode:node.left];        } else {            return nil;        }    }        // ?????????????????????    if (node.right) {        return [self search:searchValue fromNode:node.right];    } else {        return nil;    }})

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- (void)traverse:(BinarySearchTreeNode *)node {    // ??????    [self visit:node];        // ??????????    if (node.left) {        [self traverse:node.left];    }        // ??????????    if (node.right) {        [self traverse:node.right];    }})

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// ?????BinarySearchTreeNode *root = [[BinarySearchTreeNode alloc] init];root.value = 5;// ????[root insert:3 afterNode:root];    // ?????3[root insert:8 afterNode:root];    // ?????8[root insert:10 afterNode:root.right]; // ?8?????10[root insert:2 afterNode:root.left];   // ?3?????2// ????NSLog(@"??3?");BinarySearchTreeNode *node3 = [root search:3];NSLog(@"??8?");BinarySearchTreeNode *node8 = [root search:8];NSLog(@"??10?");BinarySearchTreeNode *node10 = [root search:10];NSLog(@"??1?");BinarySearchTreeNode *node1 = [root search:1];