implementStrStr.cpp

// Implement strStr().

// Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

// Clarification:

// What should we return when needle is an empty string? This is a great question to ask during an interview.

// For the purpose of this problem, we will return 0 when needle is an empty string. This is consistent to C's strstr() and Java's indexOf().
// Example 1:

// Input: haystack = "hello", needle = "ll"
// Output: 2
// Example 2:

// Input: haystack = "aaaaa", needle = "bba"
// Output: -1
// Example 3:

// Input: haystack = "", needle = ""
// Output: 0

class Solution {
public:
    int strStr(string haystack, string needle) {
        return haystack.find(needle);
    }
};