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