leetcode学习笔记(重塑矩阵/杨辉三角)

class Solution:
    def matrixReshape(self, mat: List[List[int]], r: int, c: int) -> List[List[int]]:
        if len(mat) * len(mat[0]) != r * c:
            return mat
        result = []
        row = []

        for words in mat:
            for word in words:
                row.append(word)
                if len(row) == c:
                    result.append(row)
                    row = []
                    
        return result

杨辉三角，用上一行错位相加得到下一行

class Solution:
    def generate(self, numRows: int) -> List[List[int]]:
        if numRows == 0: return []
        res = [[1]]
        while len(res) < numRows:
            newRow = [a+b for a, b in zip([0]+res[-1], res[-1]+[0])]
            res.append(newRow)      
        return res

m = [[1,2,3], [4,5,6], [7,8,9]]
n = [[2,2,2], [3,3,3], [4,4,4]]
list(zip(m))

输出：
[([1, 2, 3],), ([4, 5, 6],), ([7, 8, 9],)]

m = [[1,2,3], [4,5,6], [7,8,9]]
n = [[2,2,2], [3,3,3], [4,4,4]]
list(zip(m,n))

输出：
[([1, 2, 3], [2, 2, 2]), ([4, 5, 6], [3, 3, 3]), ([7, 8, 9], [4, 4, 4])]