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]
]

Code:

 1  vector<vector<int>> generate(int numRows) {
 2         vector<vector<int>>result;
 3         vector<int>temp;
 4         
 5         if (numRows >= 1)
 6         {
 7             temp.push_back(1);
 8             result.push_back(temp);
 9             temp.clear();
10             
11             for (int i = 1; i < numRows; ++i)
12             {
13                 for (int j = 0; j <= i; ++j)
14                 {
15                     if (j == 0)
16                         temp.push_back(result[i-1][0]);
17                     else if (j==result[i-1].size())
18                         temp.push_back(result[i-1][j-1]);
19                     else
20                         temp.push_back(result[i-1][j]+result[i-1][j-1]);
21                 }
22                 result.push_back(temp);
23                 temp.clear();
24             }
25         }
26         return result;
27     }

 

posted @ 2015-06-20 16:17  Rosanne  阅读(208)  评论(0)  编辑  收藏  举报