# 118. Pascal's Triangle
Given a non-negative integer numRows, generate the first numRows of Pascal's triangle.
In Pascal's triangle, each number is the sum of the two numbers directly above it.
Example:
Input: 5
Output:
[
[1],
[1,1],
[1,2,1],
[1,3,3,1],
[1,4,6,4,1]
]
# Solution
Approach 1: Iteration.
# Code (Python)
Approach 1:
# Code (C++)
Approach 1:
class Solution {
public:
vector<vector<int>> generate(int numRows) {
vector<vector<int>> res;
for (int i = 1; i <= numRows; ++i)
{
vector<int> row;
row.push_back(1);
for (int j = 1; j < i - 1; ++j)
{
row.push_back(res.back()[j-1] + res.back()[j]);
}
if (i > 1) row.push_back(1);
res.push_back(row);
}
return res;
}
};