Pascal's triangle@leetcode

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刷题必备书籍：Cracking the Coding Interview: 150 Programming Questions and Solutions

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]
]

» Solve this problem

弱爆题没啥好说的，下标别搞错就行了。

	class Solution {
	public:
	vector<vector<int> > generate(int numRows) {
	// Start typing your C/C++ solution below
	// DO NOT write int main() function
	vector<vector<int> > res;
	if(!numRows) return res;
	vector<int> sol;
	sol.push_back(1);
	res.push_back(sol);
	sol.clear();
	for(int i=1; i<numRows; i++)
	{
	for(int j=0; j<=i; j++)
	{
	if(j==0||j==i)
	sol.push_back(res[i-1][0]);
	else
	sol.push_back(res[i-1][j-1]+res[i-1][j]);
	}
	res.push_back(sol);
	sol.clear();
	}
	return res;
	}
	};

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