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# 118. Pascal's Triangle
"""
given an integer 'num_rows', return the first numrows of pascal's triangle.
in pascal's triangle, each number is the sum of the two number direction
above it as show [gif]
"""
class Solution(object):
def generate(self, num_rows):
ans = [[1 for _ in range(row + 1)] for row in range(num_rows)]
for row in range(num_rows):
for col in range(1, row):
ans[row][col] = ans[row - 1][col] + ans[row - 1][col - 1]
return ans
if __name__ == "__main__":
obj = Solution()
print(obj.generate(5)) # expect: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]
print(obj.generate(1)) # expect: [[1]]
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