class Solution:    # @param matrix, a list of lists of integers    # @param target, an integer    # @return a boolean    def searchMatrix(self, matrix, target):        n=len(matrix)        m=len(matrix[0])        if target>matrix[n-1][m-1] or target<matrix[0][0]:            return False        head = 0        end = n-1        mid = (end+head)//2        while mid>head and mid <end:            if target<matrix[mid][0]: end=mid            else: head=mid            mid= (end+head)//2        keyline=mid        if target>matrix[keyline][m-1]: keyline+=1        head = 0        end = m-1        mid = (end+head)//2        while mid>=head and mid <end:            if target<=matrix[keyline][mid]: end=mid            else: head=mid+1            mid= (end+head)//2                return target==matrix[keyline][mid]   if __name__==‘__main__‘:    s=Solution()    m=[[1,2,3],[4,5,6],[7,8,9]]    print(s.searchMatrix(m,3))