Implement strStr().
Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
解题思路：
这道题还是比较简答的，就是找到字符串的子串，匹配的话就返回第一个匹配值所在的index，不匹配的话就返回-1。类似与string中的indexOf方法。
[java] view plain copy print ? public class Solution { public int strStr(String haystack, String needle) { int len_needle = needle.length(); int len_haystack = haystack.length(); int n1 = 0; int h1 = 0; while(h1+len_needle<=len_haystack) { int k = h1; while(n1<len_needle && haystack.charAt(k) == needle.charAt(n1)) { n1++; k++; } if(n1 == len_needle) return h1; n1 = 0; h1++; } return -1; } } public class Solution { public int strStr(String haystack, String needle) { int len_needle = needle.length(); int len_haystack = haystack.length(); int n1 = 0; int h1 = 0; while(h1+len_needle<=len_haystack) { int k = h1; while(n1<len_needle && haystack.charAt(k) == needle.charAt(n1)) { n1++; k++; } if(n1 == len_needle) return h1; n1 = 0; h1++; } return -1; } }
