資料結構入門（第四天）

566. 重塑矩陣

class Solution:
    def matrixReshape(self, mat: List[List[int]], r: int, c: int) -> List[List[int]]:
        m,n = len(mat), len(mat[0])
        if m*n != r*c:
            return mat
        arr = []
        for row in mat:
            for x in row:
                arr.append(x)
        arr_index = 0
        newmat = [[0 for j in range(c)]for i in range(r)]
        for i in range(r):
            for j in range(c):
                newmat[i][j] = arr[arr_index]
                arr_index += 1
        return newmat
           

class Solution:
    def matrixReshape(self, nums: List[List[int]], r: int, c: int) -> List[List[int]]:
        m, n = len(nums), len(nums[0])
        if m * n != r * c:
            return nums
        
        ans = [[0] * c for _ in range(r)]
        for x in range(m * n):
            ans[x // c][x % c] = nums[x // n][x % n]
        
        return ans
           

118. 楊輝三角

class Solution:
    def generate(self, numRows: int) -> List[List[int]]:
        res = [[]for _ in range(numRows)]
        res[0] = [1]
        for i in range(1,numRows):
            res[i].append(1)
            for j in range(0,len(res[i-1])-1):
                res[i].append(res[i-1][j] + res[i-1][j+1])
            res[i].append(1)

        return res