leetcode 28. Implement strStr()
Implement strStr().Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Example 1:
Input: haystack = "hello", needle = "ll"
Output: 2
Example 2:
Input: haystack = "aaaaa", needle = "bba"
Output: -1
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().
class Solution {
public int strStr(String haystack, String needle) {
int l1 = haystack.length();
int l2 = needle.length();
for(int i = 0; i< l1 - l2 + 1; i ++){
// System.out.println(haystack.substring(i,i+l2));
if(haystack.substring(i,i+l2).equals(needle)){
return i;
}
}
return -1;
}
}
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