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Commit 2b1138c

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add q70/q104
1 parent 1991c8b commit 2b1138c

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5 files changed

+69
-17
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5 files changed

+69
-17
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‎.idea/workspace.xml‎

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‎README.md‎

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* [q21_合并两个有序链表](/src/递归/q21_合并两个有序链表)
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* [q101_对称二叉树](/src/递归/q101_对称二叉树)
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* [q104_二叉树的最大深度](/src/递归/q104_二叉树的最大深度)
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* [q226_翻转二叉树](/src/递归/q226_翻转二叉树)
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* [q236_二叉树的最近公共祖先](/src/递归/q236_二叉树的最近公共祖先)
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* [q5_最长回文子串](/src/动态规划/q5_最长回文子串)
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* [q53_最大子序和](/src/动态规划/q53_最大子序和)
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* [q70_爬楼梯](/src/动态规划/q70_爬楼梯)
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* [q118_杨辉三角](/src/动态规划/q118_杨辉三角)
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* [q300_最长上升子序列](/src/动态规划/q300_最长上升子序列)
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* [q746_使用最小花费爬楼梯](/src/动态规划/q746_使用最小花费爬楼梯)
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package 动态规划.q70_爬楼梯;
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/**
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* 动态规划 dp[i]表示到达第i阶的方法总数dp[i]=dp[i−1]+dp[i−2] o(n)
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*/
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public class Solution {
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public int climbStairs(int n) {
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if (n == 1) {
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return 1;
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}
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int[] dp = new int[n + 1];
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dp[1] = 1;
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dp[2] = 2;
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for (int i = 3; i <= n; i++) {
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dp[i] = dp[i - 1] + dp[i - 2];
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}
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return dp[n];
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}
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}
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package 递归.q104_二叉树的最大深度;
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/**
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* 递归 o(n)
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*/
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public class Solution {
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public int maxDepth(TreeNode root) {
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if (root == null) {
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return 0;
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} else {
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int leftHeight = maxDepth(root.left);
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int rightHeight = maxDepth(root.right);
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return Math.max(leftHeight, rightHeight) + 1;
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}
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}
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}
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package 递归.q104_二叉树的最大深度;
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public class TreeNode {
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int val;
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TreeNode left;
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TreeNode right;
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TreeNode(int x) {
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val = x;
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}
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}

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