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周赛 Weekly Contest 407

100372. Number of Bit Changes to Make Two Integers Equal​

class Solution:
    def minChanges(self, n: int, k: int) -> int:
        cnt = 0
        while n > 0 and k > 0:
            if k % 2 == 1:
                if n % 2 != 1:
                    return - 1
            else:
                if n % 2 == 1:
                    cnt += 1
            k >>= 1
            n >>= 1
        if k != 0:
            return - 1
        while n > 0:
            if n % 2 == 1:
                cnt += 1
            n >>= 1
        return cnt

100335. Vowels Game in a String​

  • A fails only when the Vowels count is 0
  • if Vowels count is odd
    • A just need to remove whole string
  • if Vowels count is even
    • A can remove the string with odd number of Vowels and left only one Vowels
      • If there is only one char left, B lose
      • Else, B remove a non-empty string, and A loses
class Solution:
    def doesAliceWin(self, s: str) -> bool:
        vd = {
            "a": True,
            "e": True,
            "i": True,
            "o": True,
            "u": True,
        }
        cnt = 0
        for c in s:
            if c in vd:
                cnt += 1
        # print(cnt)
        if cnt == 0:
            return False
        else:
            return True

100360. Maximum Number of Operations to Move Ones to the End​

  • Count the 1 number from left to right
  • For each "0" gap, add the previous count of 1
class Solution:
    def maxOperations(self, s: str) -> int:
        res = 0
        iCnt = 0
        i = 0
        while i < len(s):
            if s[i] == "1":
                iCnt += 1
                i += 1
            else:
                while i < len(s) and s[i] == "0":
                    i += 1
                res += iCnt
        return res

100329. Minimum Operations to Make Array Equal to Target​

  • Iterate one by one and summarize the count
class Solution:
    def minimumOperations(self, nums: List[int], target: List[int]) -> int:
        for i in range(len(nums)):
            nums[i] = target[i] - nums[i]
        # print(nums)
        i = 1
        flag = nums[0] >= 0
        cnt = abs(nums[0])
        res = cnt
        while i < len(nums):
            print(i, cnt, res, abs(nums[i]), flag, nums[i] > 0)
            if (nums[i] > 0) == flag:
                if cnt <= abs(nums[i]):
                    # print("here1")
                    res += abs(nums[i]) - cnt
                    cnt = abs(nums[i])
                else:
                    cnt = abs(nums[i])
            else:
                # print("here")
                cnt = abs(nums[i])
                flag = nums[i] > 0
                res += cnt
            i += 1
        return res