var haystack = "leetcode", needle = "ee";
var strStr = function(haystack, needle) {
var lenP = haystack.length, lenC = needle.length;
if (lenP == 0 && lenC == 0) { // 允许一个为空进行搜索
return 0;
}
if (lenP < lenC) {
return -1;
}
for (var i = 0; i < lenP - lenC + 1; i++) { // 注意i的范围
if (haystack.substr(i,lenC) == needle) {
return i;
}
}
return -1;
};
console.log(strStr(haystack,needle));