You are given two strings word1 and word2. Merge the strings by adding letters in alternating order, starting with word1. If a string is longer than the other, append the additional letters onto the end of the merged string.
Return the merged string.
Example 1
Input: word1 = "abc", word2 = "pqr"
Output: "apbqcr"
Explanation: The merged string will be merged as so:
word1: a b c
word2: p q r
merged: a p b q c r
Example 2
Input: word1 = "ab", word2 = "pqrs"
Output: "apbqrs"
Explanation: Notice that as word2 is longer, "rs" is appended to the end.
word1: a b
word2: p q r s
merged: a p b q r s
Example 3
Input: word1 = "abcd", word2 = "pq"
Output: "apbqcd"
Explanation: Notice that as word1 is longer, "cd" is appended to the end.
word1: a b c d
word2: p q
merged: a p b q c d
Constraints
- 1 <= word1.length, word2.length <= 100
- word1 and word2 consist of lowercase English letters.
Solution
双指针遍历，进去可以加两个判断，不用出来再附加尾部。
char * mergeAlternately(char * word1, char * word2){
int i, j, k, n1, n2;
n1 = strlen(word1);
n2 = strlen(word2);
char *merged = (char*)malloc(sizeof(char) * (n1 + n2 + 1));
i = j = k = 0;
while (i < n1 || j < n2 ) {
if (i < n1) merged[k++] = word1[i++];
if (j < n2) merged[k++] = word2[j++];
}
merged[k] = '\0';
return merged;
}
