Problem Link: http://oj.leetcode.com/problems/pascals-triangle-ii/ Let T[i][j] be the j-th element of the i-th row in the triangle, for 0 <= j <= i, i = 0, 1, ... And we have the recursive function for T[i][j] T[i][j] = 1, if j == 0 or j == i T[i][j…

Prolbem Link: http://oj.leetcode.com/problems/pascals-triangle/ Just a nest-for-loop... class Solution: # @return a list of lists of integers def generate(self, numRows): # Initialize the triangle res = [] for i in xrange(numRows): res.append([1] * (…

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…

Problem link: http://oj.leetcode.com/problems/linked-list-cycle-ii/ The solution has two step: Detecting the loop using faster/slower pointers. Finding the begining of the loop. After two pointers meet in step 1, keep one pointer and set anther to th…

[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…

题目简述: 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 you optimize your algorithm to use only O(k) extra space? 解题思路: 这里的关键是空间的使用,既然只能用O(K)很容易就想到我们要进行回卷(名字好像不对).我的做法是每一次都在后面新加入一个数…

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? 注意:只开辟O(K)的内存空间,所以只保存前一组数列和当前数组,并不断滚动更新即可. class Solution { public: vecto…

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? 解题思路1(实现巧妙,但时间复杂度高): 空间复杂度O(k),时间复杂度O(k^2) 和Pascal's Triangle类似,每一行数列,从后往前找…

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? 题解:简单的模拟题,每次用answer列表存放上一层的值,用temp列表存放当前层的值,只要计算好temp中需要重新计算的元素的索引范围[1,i-1]…

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] ] Subscribe to see which companies asked this question [思路] 这道题目很简单,代码如下: public class Solution { publ…