Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Example 1:
Input: haystack = "sadbutsad", needle = "sad" Output: 0 Explanation: "sad" occurs at index 0 and 6. The first occurrence is at index 0, so we return 0.
Example 2:
Input: haystack = "leetcode", needle = "leeto" Output: -1 Explanation: "leeto" did not occur in "leetcode", so we return -1.
Constraints:
1 <= haystack.length, needle.length <= 104haystack and needle consist of only lowercase English characters.class Solution {
public:
int strStr(string haystack, string needle) {
if(needle.length()>haystack.length())
return -1;
for(int i=0; i<=haystack.length()-needle.length(); i++){
if(needle==haystack.substr(i, needle.length()))
return i;
}
return -1;
}
};