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Copy pathStrStr.java
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30 lines (28 loc) · 1.13 KB
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package LeetCode.Easy.String;
public class StrStr {
public static void main(String[] args) {
System.out.println(new StrStr().strStr("aaa", "aa"));
}
/*
* 给定一个 haystack 字符串和一个 needle 字符串，在 haystack 字符串中找出
* needle 字符串出现的第一个位置 (从0开始)。如果不存在，则返回 -1。
* */
public int strStr(String haystack, String needle) {
if (needle.trim().equals("")) return 0;
// return haystack.indexOf(needle);
char[] hayArray = haystack.toCharArray();
char[] needleArray = needle.toCharArray();
int indexOfNeedle = -1;
for (int i = 0; i < hayArray.length; i++) {
if (hayArray[i] == needleArray[0]) {
for (int j = 0; j < needleArray.length; j++) {
if (i + j >= hayArray.length) return -1;
if (hayArray[i + j] != needleArray[j]) break;
if (j == needleArray.length - 1) indexOfNeedle = i;
}
if (indexOfNeedle != -1) break;
}
}
return indexOfNeedle;
}
}