Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Implement strStr(). Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.