LeetCode--Pascal's Triangle II

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?

class Solution
{
public:
    vector<int> getRow(int rowIndex)
    {
        vector<int> pre;
        vector<int> res;
        res.push_back(1);
        for(int i=1; i<=rowIndex; i++)
        {
            pre = res;
            res.clear();
            res.push_back(1);
            for(int j=1; j<pre.size(); j++)
                res.push_back(pre[j]+pre[j-1]);
            res.push_back(1);
        }
        return res;
    }
};

LeetCode--Pascal's Triangle II

时间： 2024-08-12 05:14:01

LeetCode--Pascal's Triangle II的相关文章

LeetCode——Pascal's Triangle II

Description: Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3, Return [1,3,3,1]. public class Solution { public List<Integer> getRow(int rowIndex) { List<List<Integer>> list = new ArrayList<List&

LeetCode: Pascal's Triangle II 解题报告

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

(LeetCode)Pascal's Triangle II --- 杨辉三角进阶（滚动数组思想）

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? Subscribe to see which companies asked this question 解题分析: 此处有空间的限制,因此不能正

LeetCode Pascal's Triangle II （杨辉三角）

题意:给出杨辉三角的层数k,返回最后一层.k=0时就是只有一个数字1. 思路:滚动数组计算前一半出来,返回时再复制另一半.简单但是每一句都挺长的. 1 class Solution { 2 public: 3 vector<int> getRow(int rowIndex) { 4 if(rowIndex==0) return vector<int>(1,1); //0和1特殊处理 5 if(rowIndex==1) return vector<int>(2,1); 6

LeetCode: Pascal's Triangle II [119]

[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? [题意] 给定行索引k, k从0开始,返回该索引指向的杨辉三角的行要求只能使用O(k)的额外空间 [思路] 申请两个k+1大小的数组,

Java [Leetcode 119]Pascal's Triangle II

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]. 解题思路: 每次在上一个list前面插入1,然后后面的每两个间相加赋值给前一个数. 代码描述: public class Solution { public List<Integer> getRow(int rowIndex) { List<Integer> r

leetcode 【 Pascal's Triangle II 】python 实现

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 1 class Solution: 2 # @return a list of intege

Pascal's Triangle II Leetcode java

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? 题解: 为了达到O(k)的空间复杂度要求,那么就要从右向左生成结果.相当于你提前把上一行的计算出来,当前行就可以用上一次计算出的结果计算了

leetcode 119 Pascal's Triangle II ----- java

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? 上一道题的延伸版,就是直接求出第k行的数,要求用o(k)的空间复杂度. 也是直接相加就可以了. public class Solution { pub

leetCode 119. Pascal's Triangle II 数组

119. Pascal's Triangle II 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? 代码如下:(使用双数组处理,未优化版) class Solution { public: