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
0 0
0[1]0
0[1 1]0
0[1 2 1]0
0[1 3 3 1]0
0[1 4 6 4 1]
帕斯卡三角形，它的值 a[i][j] = a[i-1][j-1] + a[i-1][j]; 注意如果i-1<0，则a[i-1]=0，也就是假设三角形周边的元素都是0
程序中我们可以直接让边缘的数值为1
vector<vector<int>> generate(int numRows) { vector<vector<int>> ret; for (int i = 0; i < numRows; ++i) { vector<int> row; for (int j = 0; j <= i; ++j) { if (j == 0 || j == i) row.push_back(1); else row.push_back(ret[i - 1][j - 1] + ret[i - 1][j]); } ret.push_back(row); } return ret; }
原文：http://www.cnblogs.com/sdlwlxf/p/5106767.html