lintcode-737-查找矩阵-python

class Solution:
    """
    @param Matrix: the input
    @return: the element which appears every row
    """
    def FindElements(self, Matrix):
        # write your code here
        w = len(Matrix[0])
        l = len(Matrix)
        List =[]
        for i in range(0, w):
            List.append(Matrix[0][i])
        for i in range(1, l):
            Set = set()
            for j in range(0, w):
                Set.add(Matrix[i][j])
            for j in range(0, len(List)):
                if j < len(List) and List[j] not in Set:
                    List.pop(j)
        return List[0]