leetcode - 随笔分类(第15页) - iyiluo

leetcode-94-easy

摘要：Binary Tree Inorder Traversal public List<Integer> inorderTraversal(TreeNode root) { List<Integer> list = new ArrayList<>(); t(root, list); return lis 阅读全文

posted @ 2022-10-13 18:01 iyiluo 阅读(19) 评论(0) 推荐(0)

leetcode-88-easy

摘要：Merge Sorted Array 思路一: 比较两个数组前面最小值，依次插入到新数组中，最后复制新数组到 num1 中 public void merge(int[] nums1, int m, int[] nums2, int n) { int[] result = new int[nums1 阅读全文

posted @ 2022-10-13 18:01 iyiluo 阅读(24) 评论(0) 推荐(0)

leetcode-83-easy

摘要：Remove Duplicates from Sorted List 思路一: 双指针,左指针记录链表最后有效位置，右指针向前扫描，遇到不重复的值，加到左指针后面，双指针依次向前 public ListNode deleteDuplicates(ListNode head) { if (head = 阅读全文

posted @ 2022-10-13 18:00 iyiluo 阅读(20) 评论(0) 推荐(0)

leetcode-70-easy

摘要：Climbing Stairs 思路一: 动态规划，假设爬上第 n 阶楼梯，完全分类只可能存在两种情况在 n-1 楼梯处直接一步上来在 n-2 楼梯处直接两步上来所以爬上第 n 阶楼梯的方法: f(n) = f(n-1) + f(n+1) public int climbStairs(int 阅读全文

posted @ 2022-10-13 09:19 iyiluo 阅读(21) 评论(0) 推荐(0)

leetcode-69-easy

摘要：Sqrt(x) 思路一: 暴力 public int mySqrt(int x) { long begin = 1L; while ((begin * begin) <= x) { begin++; } return Long.valueOf(begin).intValue() - 1; } 思路二阅读全文

posted @ 2022-10-12 18:48 iyiluo 阅读(19) 评论(0) 推荐(0)

leetcode-67-easy

摘要：Add Binary 思路一: 先计算公共部分，最后补充未计算的位置，模拟二进制加法，写的太丑了 public String addBinary(String a, String b) { char ONE = '0' + '1'; char TWO = '1' + '1'; StringBuild 阅读全文

posted @ 2022-10-11 22:13 iyiluo 阅读(27) 评论(0) 推荐(0)

leetcode-58-easy

摘要：Length of Last Word 思路一: 从后面非空格字符开始扫描，记录非空格字符个数。优化：不用 char[]，直接用 charAt() 判断 public int lengthOfLastWord(String s) { char[] chars = s.toCharArray(); i 阅读全文

posted @ 2022-10-11 17:59 iyiluo 阅读(18) 评论(0) 推荐(0)

leetcode-66-easy

摘要：Plus One 思路一: 暴力，方向想错了，不能把 digits 当做一个整数看 public int[] plusOne(int[] digits) { if (digits[digits.length - 1] != 9) { digits[digits.length - 1]++; retu 阅读全文

posted @ 2022-10-11 17:59 iyiluo 阅读(26) 评论(0) 推荐(0)

leetcode-26-easy

摘要：Remove Duplicates from Sorted Array 思路一: 双指针，左指针永远指向有效数组长度+1的位置，左指针只会在出现交换后向右移动。右指针一直向右扫描，遇到不重复的数字就和左指针交换。 public int removeDuplicates(int[] nums) { i 阅读全文

posted @ 2022-10-11 17:58 iyiluo 阅读(23) 评论(0) 推荐(0)

leetcode-35-easy

摘要：Search Insert Position 思路一: 二分查找，然后处理没有找到的情况 public int searchInsert(int[] nums, int target) { int i = Arrays.binarySearch(nums, target); if (i >= 0) 阅读全文

posted @ 2022-10-10 18:03 iyiluo 阅读(9) 评论(0) 推荐(0)

leetcode-14-easy

摘要：Longest Common Prefix 思路一: 取第一个字符串为基准，依次对比剩余的字符串，取公共串 private static int commonPrefix(char[] arr1, char[] arr2) { int n = Math.min(arr1.length, arr2.l 阅读全文

posted @ 2022-10-10 18:02 iyiluo 阅读(15) 评论(0) 推荐(0)

leetcode-20-easy

摘要：Valid Parentheses 思路一: 用栈处理,括号匹配就出栈，如果最后栈不为空，说明输入的括号不匹配 public boolean isValid(String s) { char[] chars = s.toCharArray(); Deque<Character> stack = ne 阅读全文

posted @ 2022-10-10 18:02 iyiluo 阅读(9) 评论(0) 推荐(0)

leetcode-27-easy

摘要：remove element 思路一: 先排序，然后去除数字 public static int removeElement(int[] nums, int val) { Arrays.sort(nums); int INVALID = -1; int L = INVALID; for (int i 阅读全文

posted @ 2022-10-10 18:01 iyiluo 阅读(22) 评论(0) 推荐(0)

leetcode-21-easy

摘要：merge two sorted lists 思路一: 暴力求解，依次把两链表元素插入到新链表中 public ListNode mergeTwoLists(ListNode list1, ListNode list2) { if (list1 == null && list2 == null) r 阅读全文

posted @ 2022-10-09 17:53 iyiluo 阅读(22) 评论(0) 推荐(0)

leetcode-13-easy

摘要：Roman to Integer 思路一: 暴力求解，遍历字符，遇到 6 种特殊的组合字符单独计算 static Map<Character, Integer> map = new HashMap<>(); static Map<String, Integer> combine = new Hash 阅读全文

posted @ 2022-10-09 17:15 iyiluo 阅读(19) 评论(0) 推荐(0)

leetcode-9-easy

摘要：回文数思路一: 暴力求解，把数字一个一个拆分，放队列里面，最后取队列的首尾，对比是否相同 public static boolean isPalindrome2(int x) { if (x < 0) return false; if (x < 10) return true; Deque<Int 阅读全文

posted @ 2022-10-09 14:48 iyiluo 阅读(26) 评论(0) 推荐(0)

leetcode-1-easy

摘要：思路一:暴力求解 public int[] twoSum(int[] nums, int target) { for(int i = 0; i < nums.length; i++) { for(int j = i+1; j < nums.length; j++) { if (nums[i] + n 阅读全文

posted @ 2022-10-09 11:15 iyiluo 阅读(14) 评论(0) 推荐(0)

leetcode-2078-easy

摘要：思路一：分别用两个 map 记录最大值和最小值，然后遍历这两个 map 求得最大距离 public int maxDistance(int[] colors) { Map<Integer, Integer> min = new HashMap<>(); Map<Integer, Integer> m 阅读全文

posted @ 2022-10-09 10:59 iyiluo 阅读(23) 评论(0) 推荐(0)

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随笔分类 - leetcode

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