Climbing StairsYou are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?python code：class Solution: # @param {integer} n # @return {integer} def climbStairs(self, n): if n<=0: #illegal input return 0 else: if...
Problem:
Given an array and a value, remove all instances of that value in place and return the new length.
The order of elements can be changed. It doesn‘t matter what you leave beyond the new length.Solution:和26题一样，就是判断条件不一样而已。题目大意：给一个数组，要求返回删除所有指定元素的数组。好鸡冻，第一次全部通过，没有一个错误（虽然题目比较简单）。。。。。。贴图留念：Java源代码（248ms）：...
LeetCode 面试题03. 数组中重复的数字【剑指Offer】【Easy】【Python】【数组】【哈希表】【排序】问题力扣找出数组中重复的数字。在一个长度为 n 的数组 nums 里的所有数字都在 0～n-1 的范围内。数组中某些数字是重复的，但不知道有几个数字重复了，也不知道每个数字重复了几次。请找出数组中任意一个重复的数字。示例 1：输入：
[2, 3, 1, 0, 2, 5, 3]
输出：2 或 3 限制：2 <= n <= 100000思路解法一哈希表遍历数组，未出现过的...
最小栈 设计一个支持 push，pop，top 操作，并能在常数时间内检索到最小元素的栈。push(x)?-- 将元素 x 推入栈中。pop()?-- 删除栈顶的元素。top()?-- 获取栈顶元素。getMin() -- 检索栈中的最小元素。Python语言：使用辅助栈记录小的元素class MinStack:def __init__(self):"""initialize your data structure here."""self.stack=[]self.minstack=[]self.length = 0def push(self, x: int) -> None:self.stack.append(x)if se...
看似简单，实际上想了挺久的1）内置api方法class Solution:def merge(self, nums1: List[int], m: int, nums2: List[int], n: int) -> None:"""Do not return anything, modify nums1 in-place instead."""while nums1 and nums1[-1] == 0:if len(nums1) == m:breakdel nums1[-1]nums1 += nums2nums1.sort()2）双指针，哪个小输入哪个，再替换Nums1temp = []p1 = 0p2 = 0while(p1 < m and p2 < n):if (nums1[p1] <= nums2[p2]):tem...
题目：Given an index k, return the kth row of the Pascal‘s triangle.For example, given k = 3,Return [1,3,3,1].Note:Could you optimize your algorithm to use only O(k) extra space? 代码：oj测试通过 Runtime: 48 ms 1class Solution:2# @return a list of integers 3def getRow(self, rowIndex):4if rowIndex == 0:5return [1]6if rowIndex == 1:7return [1,1]8 pascal = [1,1]9for i in range(1,rowIndex):
1...
问题描述： Given an integer n, return the number of trailing zeroes in n!. Example 1: Input: 3
Output: 0
Explanation: 3! = 6, no trailing zero. Example 2: Input: 5
Output: 1
Explanation: 5! = 120, one trailing zero. Note: Your solution should be in logarithmic time complexity. 思路：在n!中，若想在结果的结尾产生0，只能是5乘以双数、或者某个乘数结尾为0，如10，但10可视为5*2，20可以视为5*4.综上要想找n!...
Word Break Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.For example, givens = "leetcode",dict = ["leet", "code"].Return true because "leetcode" can be segmented as "leet code". python code：class Solution: # @param s, a string # @param wordDict, a set<string> # @return a boolean def word...
Given an unsorted integer array, find the first missing positive integer.
For example,
Given [1,2,0] return 3,
and [3,4,-1,1] return 2.Your algorithm should run in O(n) time and uses constant space.这题用的是count sort 的方法。首先我们来复习一下count sort已知一个正整数还未排列数列。 先遍历一遍得到最大值，建一个counter数组。再将counter里面的数依次赋值到原来的数组当中去。代码如下def counts(A):maxval...
题目：填充每个节点的下一个右侧节点指针：给定一个完美二叉树，其所有叶子节点都在同一层，每个父节点都有两个子节点。给定一个完美二叉树，其所有叶子节点都在同一层，每个父节点都有两个子节点。二叉树定义如下：struct Node { int val; Node *left; Node *right; Node *next;}填充它的每个 next 指针，让这个指针指向其下一个右侧节点。如果找不到下一个右侧节点，则将 next 指针设置为 NULL。初始状态下，所有 next 指针都...
ProblemLeetCodeGiven a Binary Search Tree (BST) with the root node root, return the minimum difference between the values of any two different nodes in the tree.Example :Input: root = [4,2,6,1,3,null,null]
Output: 1
Explanation:
Note that root is a TreeNode object, not an array.The given tree [4,2,6,1,3,null,null] is represented by the following diagram:4/ 2 6/ \ 1 3 while the m...
问题描述：给出一个无重叠的 ，按照区间起始端点排序的区间列表。在列表中插入一个新的区间，你需要确保列表中的区间仍然有序且不重叠（如果有必要的话，可以合并区间）。示例 1:输入: intervals = [[1,3],[6,9]], newInterval = [2,5]输出: [[1,5],[6,9]]示例 2:输入: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]输出: [[1,2],[3,10],[12,16]]解释: 这是因为新的区间 [4,8] 与 [3,5],[6,7],[8,10] 重叠...
存在一个按升序排列的链表，给你这个链表的头节点 head ，请你删除链表中所有存在数字重复情况的节点，只保留原始链表中 没有重复出现 的数字。返回同样按升序排列的结果链表。提示：链表中节点数目在范围 [0, 300] 内-100 <= Node.val <= 100题目数据保证链表已经按升序排列# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next =...
Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.Below is one possible representation of s1 = "great": great/ gr eat/ \ / g r e at/ a t
To scramble the string, we may choose any non-leaf node and swap its two children.For example, if we choose the node "gr" and swap its two children, it produces a scr...
题目来源： https://leetcode.com/problems/sudoku-solver/ 题意分析： 这次的题目就是上一题的进化版。填好一个数独。 题目思路： 这题直接用dfs暴力解决。把“*”用（1-9）直接填就行。时间复杂度比较高。要注意的是，题目要求没有返回值，所以要另外写一个函数用来判断填数之后是否满足可以填好。 代码（python）： 1class Solution(object):2def isValue(self,board,x,y):3#列符合 4for i in range(9):5if i != x and...