Leetcode 2914. Minimum Number of Changes to Make Binary String Beautiful

  • [Leetcode 2914. Minimum Number of Changes to Make Binary String Beautiful](#Leetcode 2914. Minimum Number of Changes to Make Binary String Beautiful)
    • [1. 解题思路](#1. 解题思路)
    • [2. 代码实现](#2. 代码实现)

1. 解题思路

这一题思路很简单,就是一个贪婪算法。

显然,从头往后考察每一个字符,如果它与前一个字符不相同,那么我们必然只有两个选择:

  1. 如果前面刚好为偶数个字符,那么直接在此处截断即可;
  2. 如果前面为奇数个字符,那么必然要将这个字符反转,此时同样可以在此处截断,因为不会影响后续结果。

这么一来,事实上贪婪算法的结果就必然是最小结果,我们直接给出答案即可。

2. 代码实现

给出python代码实现如下:

python 复制代码
class Solution:
    def minChanges(self, s: str) -> int:
        ans = 0
        pre, cnt = "", 0
        for ch in s:
            if ch == pre:
                cnt += 1
            else:
                if cnt % 2 == 0:
                    pre = ch
                    cnt = 1
                else:
                    ans += 1
                    cnt = 0
        return ans

提交代码评测得到:耗时72ms,占用内存17.3MB。

相关推荐
Espresso Macchiato1 个月前
Leetcode 3316. Find Maximum Removals From Source String
leetcode·动态规划·leetcode medium·leetcode 3316·leetcode双周赛141
Espresso Macchiato2 个月前
Leetcode 3306. Count of Substrings Containing Every Vowel and K Consonants II
leetcode·滑动窗口·leetcode medium·leetcode 3306·leetcode周赛417
Espresso Macchiato2 个月前
Leetcode 3301. Maximize the Total Height of Unique Towers
leetcode·leetcode medium·leetcode双周赛140·leetcode 3301
Espresso Macchiato2 个月前
Leetcode 3302. Find the Lexicographically Smallest Valid Sequence
leetcode medium·lcs·leetcode 3302·leetcode双周赛140·最大公共子序列
Espresso Macchiato3 个月前
Leetcode 3255. Find the Power of K-Size Subarrays II
leetcode·leetcode medium·leetcode 3255·leetcode 3254·leetcode周赛137
Espresso Macchiato4 个月前
Leetcode 3240. Minimum Number of Flips to Make Binary Grid Palindromic II
leetcode·leetcode medium·回文·leetcode 3240·leetcode双周赛136
Espresso Macchiato4 个月前
Leetcode 3234. Count the Number of Substrings With Dominant Ones
排列组合·leetcode medium·容斥原理·leetcode 3234·leetcode周赛408
Espresso Macchiato5 个月前
Leetcode 3201. Find the Maximum Length of Valid Subsequence I
leetcode medium·leetcode题解·leetcode 3201·leetcode周赛404
Espresso Macchiato5 个月前
Leetcode 3196. Maximize Total Cost of Alternating Subarrays
leetcode·动态规划·leetcode medium·leetcode周赛403·leetcode 3196
Espresso Macchiato5 个月前
Leetcode 3195. Find the Minimum Area to Cover All Ones I
leetcode·leetcode medium·leetcode题解·leetcode 3195·leetcode周赛403