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]

]

	vector<vector<int>> generate(int numRows) {
		vector<vector<int>> val;
		val.resize(numRows);
		for (int i=0; i<numRows; i++)
		{
			//pascal三角形，第i行元素个数为i+1(i从0开始）
			val[i].resize(i+1);
			//首位元素都为1
			val[i][0]=1;
			val[i][val[i].size()-1]=1;
			//中间元素满足：A[k][n]=A[k-1][n-1]+A[k-1][n]
			for (int j=1; j<val[i].size()-1; j++)
			{
				val[i][j]=val[i-1][j-1]+val[i-1][j];
			}
		}
		return val;
	}

Pascal's Triangle

时间： 2024-08-01 01:43:17

Pascal's Triangle的相关文章

（leetcode题解）Pascal's Triangle

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] ] 题意实现一个杨辉三角. 这道题只要注意了边界条件应该很好实现出来,C++实现如下 vector<vector<int>> generate(int

LeetCode (13) Pascal's Triangle (杨辉三角 )

题目描述 Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5, Return 从第三行开始,每行除了最左边和最右边两个数为1,其他数字都是上一行中相邻两个数字之和.根据上述规则可以写出下面的代码: class Solution { public: vector<vector<int> > generateRow1() { vector<in

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] ] 分析第k层有k个元素,每层第一个及最后一个元素值为1,对于(k>2)层,第n(n>1 && n < k)个元素A[k][n] = A[k-1][n-1]+A[k-1][n];

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? 1 class Solution { 2 public: 3 vector<int> getRow(int rowIndex) { 4 5 vect

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 OJ：Pascal's Triangle（帕斯卡三角）

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] ] 帕斯卡三角,很简单的问题,见代码: 1 class Solution { 2 public: 3 vector<vector<int>> generate(int numRows) {

Pascal's Triangle II 解答

Question Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3,Return [1,3,3,1]. Solution Similar with Pascal's Triangle. Note that the index starts from 0. 1 public class Solution { 2 public List<Integer> getRow(in

[leedcode 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]. public class Solution { public List<Integer> getRow(int rowIndex) { //由于需要O(k)空间,因此需要借助两个数组保存中间值,并交换两个数组,注意交换的方法! List<Integer> list=new

LeetCode——Pascal's Triangle

Description: 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] ] public class Solution { public List<List<Integer>> generate(int numRows) { List

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&