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]
]

源码

vector<vector<int>> generate(int numRows) {
    vector<vector<int>> result(numRows);
    for(int i = 0; i < numRows; i++){
        result[i].resize(i + 1);
        result[i][0] = result[i][i] = 1;
        // 1 到 i - 1 元素
        for(int j = 1; j<i; j++) 
            result[i][j] = result[i-1][j-1] + result[i-1][j];
    }
    return result;
}