每日三题（1）

class Solution:
    def findRepeatNumber(self, nums: List[int]) -> int:
        nums.sort()
        pre = nums[0]
        for i in range(1,len(nums)):
            if pre == nums[i]:
                return pre
            pre=nums[i]

class Solution:
    def findRepeatNumber(self, nums: List[int]) -> int:
        newset={}
        for num in nums:
            if num not in newset:
                newset[num]=1
            else:
                return num

class Solution:
    def findNumberIn2DArray(self, matrix: List[List[int]], target: int) -> bool:
        if len(matrix)==0:
            return False
        row = 0
        col = len(matrix[0])-1
        while row<len(matrix) and col>=0:
            if matrix[row][col]==target:
                return True
            elif target > matrix[row][col]:
                row += 1
            else:
                col -=1
        return False

class Solution:
    def replaceSpace(self, s: str) -> str:
        return s.replace(" ", "%20")

class Solution:
    def replaceSpace(self, s: str) -> str:
        if len(s)==0:
            return ""
        newList=list(s)
        for i in range(len(s)):
            if newList[i]==" ":
                newList[i]="%20"
        return ‘‘.join(newList)