Implement strStr().
Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
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class Solution { public: int strStr(string haystack, string needle) { int i,j; for (i = j = 0; haystack[i] && needle[j];) { if (haystack[i] == needle[j]) { ++i; ++j; } else { i = i - j + 1; j = 0; } } return needle[j] ? -1 : (i - j); } };
原文：http://www.cnblogs.com/SpeakSoftlyLove/p/5119799.html