leetcode28: Implement strStr()

                                                 Implement strStr

Implement strStr().

Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

对haystack进行遍历，比较当前下标下，长度为needle.length()长的字符串是否与needle相等，是则返回，否则，继续下一组比较

package leetcode;public class leet28 {public static void main(String[] args) {leet28 leet = new leet28();System.out.println(leet.strStr("abcde","db"));}public int strStr(String haystack,String needle){for(int i = 0;i < haystack.length();i++){int j = 0;for(j = 0;j < needle.length();j++){if(haystack.charAt(i+j) != needle.charAt(j)){break;}}if(j == needle.length()){return i;}}return -1;}}