BF算法学习笔记

var str1 = "ABC ABB ACF";
var str2 = "ABB";
var bValue = this.BF_ordinary(str1, str2);

/////////
//暴力算法
//递归版本
/////////
BF_Recursive：function (sourceStr, searchStr, offset) {
var mainLength = sourceStr.length;
var searchLength = searchStr.length;
if (searchLength > mainLength - offset) {
return -1;
}
offset = offset || 0;
for (var i = 0; searchLength > i; i++) {
if (searchStr.charAt(i) !== sourceStr.charAt(offset + i)) {
return BF_Recursive(sourceStr, searchStr, offset + 1)
}
}
return offset;
}

BF_ordinary: function(sourceStr, searchStr){
var sourceLen = sourceStr.length;
var searchLen = searchStr.length;
var padding = sourceLen - searchLen;
/*方式1*/
for(var i = 0; i <= padding; i++){
if(sourceStr.charAt(i) == searchStr.charAt(0)){
var complete = searchLen;
for(var j = 0; j < searchLen; j++){
if(sourceStr.charAt(i+j) == searchStr.charAt(j)){
--complete;
if(!complete){
return i;
}
}
}
}
}
return -1;

/*方法二*/
for(var offset = 0; offset < padding; offset++){
var match = true;
for(var i = 0; i < searchLen; i++){
if(searchStr.charAt(i) !== sourceStr.charAt(offset+i)){
match = false;
break;
}
}
if(match){
return offset;
}
}
return -1;

/*方法三*/
var i = 0,
j = 0;
while(i < sourceLen){
if(sourceStr.charAt(i) == searchStr.charAt(j)){
i++;
j++;
}else{
i = i - j + 1;
j = 0;
}
if(j == searchLen){
return i - j;
}
}
}

参考原作：http://www.cnblogs.com/aaronjs/p/4218650.html