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]
]

解决方案:

vector<vector<int>> generate(int numRows) {
vector<vector<int>> res = {};
for (int i = 0; i < numRows; i++) {
res.push_back(vector<int>(i + 1, 1));
for(int j = 1; j < i; j++) {
res[i][j] = (res[i - 1][j] + res[i - 1][j - 1]);
}
}
return res; }

Pascal's Triangle II
Total Accepted: 46342
Total Submissions: 157260

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?

我的解决方案:

从没一行的倒数第二个算起,往前面逆推:

 vector<int> getRow(int rowIndex)
{
vector<int> result(rowIndex + 1, 1); for(int i = 1; i <= rowIndex; ++i)
{
for(int j = i - 1; j > 0; --j)
{
result[j] = result[j] + result[j - 1];
}
} return result;
}

递归的解决方案:

vector<int> getRow(int rowIndex) {
vector<int> result; if (rowIndex == 0) {
result.push_back(1); return result;
} else {
vector<int> vec = getRow(rowIndex - 1);
result.push_back(1);
for (size_t i = 0; i < vec.size() - 1; i++) {
result.push_back(vec[i] + vec[i+1]);
}
result.push_back(1);
}
}

python 解决方案:

class Solution:
# @param {integer} rowIndex
# @return {integer[]}
def getRow(self, rowIndex):
row = [1]
for i in range(1, rowIndex+1):
row = list(map(lambda x,y: x+y, [0]+row, row + [0]))
return row

leetcode 生成杨辉三角形, 118 119 Pascal's Triangle 1,2的更多相关文章

  1. 【LeetCode】118 & 119 - Pascal's Triangle & Pascal's Triangle II

    118 - Pascal's Triangle Given numRows, generate the first numRows of Pascal's triangle. For example, ...

  2. 118/119. Pascal's Triangle/II

    原文题目: 118. Pascal's Triangle 119. Pascal's Triangle II 读题: 杨辉三角问题 '''118''' class Solution(object): ...

  3. leetcode 生成杨辉三角形, 118 119 Pascal's Triangle 1,2

    Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5, Retu ...

  4. 118. 119. Pascal's Triangle -- 杨辉三角形

    118. Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5, ...

  5. leetcode 118. Pascal's Triangle 、119. Pascal's Triangle II 、120. Triangle

    118. Pascal's Triangle 第一种解法:比较麻烦 https://leetcode.com/problems/pascals-triangle/discuss/166279/cpp- ...

  6. LeetCode OJ 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, ...

  7. [LeetCode] 119. Pascal's Triangle II 杨辉三角之二

    Given a non-negative index k where k ≤ 33, return the kth index row of the Pascal's triangle. Note t ...

  8. [LeetCode]题解(python):119 Pascal's Triangle II

    题目来源 https://leetcode.com/problems/pascals-triangle-ii/ Given an index k, return the kth row of the ...

  9. LeetCode 119. Pascal's Triangle II (杨辉三角之二)

    Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3,Return [1,3, ...

随机推荐

  1. phpstorm查看类的继承关系

    在看一些框架源码时,有些类有很多的继承或者接口,有一款神奇的帮助很重要 选中一个类文件,右键,选择diagrams->show diagrams 即可得到类的继承关系,如上右图 使用函数 fun ...

  2. plsql和tsql常用函数比较

    数学函数 .绝对值 S:) value O:) value from dual .取整(大) S:select ceiling(-1.001) value O:select ceil(-1.001) ...

  3. 纯CSS菜单样式,及其Shadow DOM,Json接口 实现

    先声明,要看懂这篇博客要求你具备少量基础CSS知识, 当然如果你只是要用的话就随便了,不用了解任何知识 完整项目github链接:https://github.com/git-Code-Shelf/M ...

  4. Linux中MySQL忽略表中字段大小写

    linux 下,mysql 的表面默认是区分大小写的,windows 下默认不区分大小写,我们大多数在windows 下开发,之后迁移到linux(特别是带有Hibernate的工程),可以修改配置是 ...

  5. 无法启动postgresql的错误

    chown postgres /etc/ssl/private/ssl-cert-snakeoil.key chgrp postgres /etc/ssl/private/ssl-cert-snake ...

  6. SimpleDateFormat中parse和format的区别

    parse()返回的是一个Date类型数据,format返回的是一个StringBuffer类型的数据 //SimpleDateFormat中的parse方法可以 //把String型的字符串转换成特 ...

  7. SOAP Binding: Difference between Document and RPC Style Web Services

    SOAP Binding: Difference between Document and RPC Style Web Services 20FLARES Twitter 1Facebook 9Goo ...

  8. Switch控件详解

    Switch控件详解 原生效果 5.x 4.x 布局 <Switch android:id="@+id/setting_switch" android:layout_widt ...

  9. Android 实现串口的移植

    安卓串口的实现,需要底层C++配合,不过这次我们根据framework中的思想,直接用API修改提供给JAVA层调用,这个就比较简单了. DEV项目需要,要实现在Android中实现串口的收发功能,有 ...

  10. Matplotlib Toolkits:python高级绘图库seaborn

    http://blog.csdn.net/pipisorry/article/details/49515745 Seaborn介绍 seaborn (Not distributed with matp ...