leetcode/algorithms/java/src/strStr/strStr.java at master · wcoder0/leetcode · GitHub

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// Source : https://oj.leetcode.com/problems/implement-strstr/

// Inspired by : http://www.jiuzhang.com/solutions/implement-strstr/

// Author : Lei Cao

// Date : 2015-10-02

/**********************************************************************************

* Implement strStr().

* Returns a pointer to the first occurrence of needle in haystack, or null if needle is not part of haystack.

**********************************************************************************/

package strStr;

/**

* Created by leicao on 2/10/15.

public class strStr {

public int strStr(String haystack, String needle) {

if (haystack == null || needle == null) {

return -1;

}

int i, j = 0;

for (i = 0; i < haystack.length() - needle.length() + 1; i++) {

for (j = 0; j < needle.length(); j++) {

if (haystack.charAt(i + j) != needle.charAt(j)) {

break;

}

if (j == needle.length()) {

return i;

}

return -1;

}