剖析二指针技术

def reversewords(s: str) -> str:    words = s.split()  # split the input string into words    for i in range(len(words)):        left = 0  # initialize the left pointer        right = len(words[i]) - 1  # initialize the right pointer        split_word = list(words[i])  # convert the word into a list of characters        while left < right:  # continue until the pointers meet in the middle            # swap the characters at the left and right pointers            temp = split_word[left]            split_word[left] = split_word[right]            split_word[right] = temp            left += 1  # move the left pointer to the right            right -= 1  # move the right pointer to the left        words[i] = "".join(split_word)  # rejoin the characters into a word    return " ".join(words)  # join the reversed words into a final string

def mergeAlternately(word1: str, word2: str) -> str:    # Initialize an empty list to store the merged characters    word_list = []    # Initialize two pointers, starting at the beginning of each word    pointer_1 = 0    pointer_2 = 0    # Loop until one of the pointers reaches the end of its respective word    while pointer_1 < len(word1) and pointer_2 < len(word2):        # Append the character from word1 at pointer_1 to the list        word_list.append(word1[pointer_1])        # Append the character from word2 at pointer_2 to the list        word_list.append(word2[pointer_2])        # Move both pointers forward by one position        pointer_1 += 1        pointer_2 += 1    # If there are remaining characters in word1, add them to the list    if pointer_1 < len(word1):        word_list.append(word1[pointer_1:])    # If there are remaining characters in word2, add them to the list    if pointer_2 < len(word2):        word_list.append(word2[pointer_2:])    # Join the list of characters into a single string and return it    return "".join(word_list)