详解平衡二叉树(AVL tree)平衡操作(图+代码)

 

* 左左就右旋，右右就左旋

 

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
const int maxn = 1e9;
const int maxm = 1e5 + 5;
const int inf = 2147483647;
using namespace std;
struct node {
    node *left, *right;
    int key;
};

node *LL(node *root) {
    node *t = root->left;
    root->left = t->right;
    t->right = root;
    return t;
}

node *RR(node *root) {
    node *t = root->right;
    root->right = t->left;
    t->left = root;
    return t;
}

node *RL(node *root) {
    root->right = LL(root->right);
    return RR(root);
}

node *LR(node *root) {
    root->left = RR(root->left);
    return LL(root);
}

int getHight(node *root) {
    if (root == NULL)return 0;
    return max(getHight(root->left), getHight(root->right)) + 1;
}

node *insert(node *root, int val) {
    if (root == NULL) {
        root = new node();
        root->key = val;
        root->left = root->right = NULL;
    } else if (val < root->key) {
        root->left = insert(root->left, val);
        if (getHight(root->left) - getHight(root->right) == 2)
            root = val < root->left->key ? RR(root) : LR(root);
    } else {
        root->right = insert(root->right, val);
        if (getHight(root->right) - getHight(root->left) == 2)
            root = val > root->right->key ? LL(root) : RL(root);
    }
    return root;
}

int main() {
    int n, k;
    cin >> n;
    node *root = NULL;
    for (int i = 1; i <= n; i++) {
        cin >> k;
        root = insert(root, k);
    }
    return 0;
}