leetcode 28

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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Seen this question in a real interview before?   

Yes

 

我的代码比较复杂，效率也不高，其中应该用数据结构说到过关于字符串匹配的预处理，我没做

结果就是33%的效率，看了别的答案，恩，用javascript内部indexof函数，恩，不错top1

下面两个代码

var strStr = function(haystack, needle) {    if(needle==''){        return 0;    }    if(haystack.length<needle.length || (haystack.length==0 && needle.length!=0)){        return -1;    }    for(var i=0;i<haystack.length;i++){        var flag=0;        for( var j=0;j<needle.length;j++){            if(haystack[i+j]!=needle[j]){                flag=1;                break;            }        }        if(flag==0){            return i;        }    }    return -1;};

/** * @param {string} haystack * @param {string} needle * @return {number} */var strStr = function(haystack, needle) {    return haystack.indexOf(needle);};