The provided solution intends to merge two strings word1 and word2 by alternating characters from each. It begins by identifying the length of the shorter string (w). It then slices both strings into parts that have equivalent indices (c and d) and the leftover parts (e and f) when one string is longer than the other. In a loop, it alternates adding characters from c and d to a new string s, but it inserts them in reverse order, hence the need to reverse s at the end. After the loop, it appends any leftover characters from the longer string.
时间复杂度: O(n)
空间复杂度: O(n)
class Solution:
def mergeAlternately(self, word1: str, word2: str) -> str:
w = min(len(word1), len(word2)) # Find the length of the shorter word
c = word1[:w] # Characters from word1 that will be alternated
d = word2[:w] # Characters from word2 that will be alternated
e = word1[w:] # Remaining characters of word1 if it is longer
f = word2[w:] # Remaining characters of word2 if it is longer
s = '' # Initialize the result string
for i in range(w): # Alternate characters
s = c[i] + s # Prepend characters from word1 in reverse
s = d[i] + s # Prepend characters from word2 in reverse
return s[::-1] + e + f # Reverse the string and append remaining parts