Given an index k, return the k th 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? 题意:给定整数K,返回行下标为K的数组. 思路:  关键点是,每次遍历数组时都是从后往前遍历,因为从前往后遍历,没有办法保存之前所得到的信息.若从前…

当我们需要改变数组的值时,如果从前往后遍历,有时会带来很多麻烦,比如需要插入值,导致数组平移,或者新的值覆盖了旧有的值,但旧有的值依然需要被使用.这种情况下,有时仅仅改变一下数组的遍历方向,就会避免这些困难. 最直观的一题是 剑指Offer上的面试题 4 另外一道例题,就是LeetCode上的 Pascal's Triangle II Pascal's Triangle II Given an index k, return the kth row of the Pascal's triangl…

118. Pascal's Triangle 第一种解法:比较麻烦 https://leetcode.com/problems/pascals-triangle/discuss/166279/cpp-beats-1002018.9.3(with-annotation) class Solution { public: vector<vector<int>> generate(int numRows) { vector<vector<int>> result;…

[LeetCode]Pascal's Triangle II 解题报告 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/pascals-triangle-ii/description/ 题目描述: 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 yo…

118 - Pascal's Triangle Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5,Return [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] Solution: class Solution { public: vector<vector<int>> generate(int n…

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? [思路] 我们为了满足空间复杂度的要求,我们新建两个ArrayList,一个负责存储上一个Pascal行的结果,一个根据上一个Pascal行得出当前P…

Pascal's Triangle II Total Accepted: 19384 Total Submissions: 63446 My Submissions Question SolutionGiven 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 us…

Pascal's Triangle Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5,Return [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] class Solution: # @return a list of lists of integers def generate(self, numRows):…

package y2019.Algorithm.array; import java.util.ArrayList; import java.util.List; /** * @ProjectName: cutter-point * @Package: y2019.Algorithm.array * @ClassName: GetRow * @Author: xiaof * @Description: 119. Pascal's Triangle II * Given a non-negativ…

杨辉三角形II(Pascal's Triangle II) 问题 给出一个索引k,返回杨辉三角形的第k行. 例如,给出k = 3,返回[1, 3, 3, 1] 注意: 你可以优化你的算法使之只使用O(k)的额外空间吗? 初始思路 首先来复习复习杨辉三角形的性质(来自wiki): 杨辉三角以正整数构成,数字左右对称,每行由1开始逐渐变大,然后变小,回到1. 第行的数字个数为个. 第行的第个数字为组合数. 第行数字和为. 除每行最左侧与最右侧的数字以外,每个数字等于它的左上方与右上方两个数字之和(也…