Created
July 17, 2015 22:23
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Trie implementation
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function Trie() { | |
this.head = { | |
key : '' | |
, children: {} | |
} | |
} | |
Trie.prototype.add = function(key, value) { | |
var curNode = this.head | |
, newNode = null | |
, curChar = key.slice(0,1); | |
key = key.slice(1); | |
while(typeof curNode.children[curChar] !== "undefined" | |
&& curChar.length > 0){ | |
curNode = curNode.children[curChar]; | |
curChar = key.slice(0,1); | |
key = key.slice(1); | |
} | |
while(curChar.length > 0) { | |
newNode = { | |
key : curChar | |
, value : key.length === 0 ? null : undefined | |
, children : {} | |
}; | |
curNode.children[curChar] = newNode; | |
curNode = newNode; | |
curChar = key.slice(0,1); | |
key = key.slice(1); | |
} | |
}; | |
Trie.prototype.search = function(key) { | |
var curNode = this.head | |
, curChar = key.slice(0,1) | |
, d = 0; | |
key = key.slice(1); | |
while(typeof curNode.children[curChar] !== "undefined" && curChar.length > 0){ | |
curNode = curNode.children[curChar]; | |
curChar = key.slice(0,1); | |
key = key.slice(1); | |
d += 1; | |
} | |
if (curNode.value === null && key.length === 0) { | |
return d; | |
} else { | |
return -1; | |
} | |
} | |
Trie.prototype.remove = function(key) { | |
var d = this.search(key); | |
if (d > -1){ | |
removeH(this.head, key, d); | |
} | |
} | |
function removeH(node, key, depth) { | |
if (depth === 0 && Object.keys(node.children).length === 0){ | |
return true; | |
} | |
var curChar = key.slice(0,1); | |
if (removeH(node.children[curChar], key.slice(1), depth-1)) { | |
delete node.children[curChar]; | |
if (Object.keys(node.children).length === 0) { | |
return true; | |
} else { | |
return false; | |
} | |
} else { | |
return false; | |
} | |
} | |
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