Create 二叉树之层次遍历.js

Author: Rain120

二叉树之层次遍历.js

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+/*
+ * 
+ * 输入：(11,LL)(7,LLL)(8,R)(5,)(4,L)(13,RL)(2,LLR)(1,RRR)(4,RR)
+ * 输出：5 4 8 11 13 4 7 2 1
+ * 思路：先建立一棵二叉树。再进行队列遍历。
+ *
+ */
+function beTree(obj) {
+		var obj = obj.split(')');
+		var newobj = [];
+		for (var i = 0; i < obj.length - 1; i++) {
+				newobj.push(obj[i].replace('(',''));
+		}
+		var root = {
+				value: null, left: null, right: null, child: false
+		}
+		var node;
+		for(var i = 0; i < newobj.length; i++) {
+				var [nodeVal, nodePos] = newobj[i].split(',');
+				node = root;
+				if(nodePos){
+						for (var j = 0; j < nodePos.length; j++) {
+
+								if(nodePos[j].toUpperCase() === 'L'){
+										if(node.left === null){
+												node.left = newnode();
+												node = node.left;
+										}else {
+												node = node.left;
+										}
+								} else if(nodePos[j].toUpperCase() === 'R') {
+										if(node.right === null){
+												node.right = newnode();
+												node = node.right;
+										}else{
+												node = node.right;
+										}
+								}
+						}
+						if(!node.child) {
+								node.value = nodeVal;
+								node.child = true;
+						}
+				}else {
+						root.value = nodeVal;
+						node.child = true;
+				}
+		}
+		return root;
+}
+function newnode() {
+		return { value: null, left: null, right: null, child: false };
+}
+function bfs() {
+		var root = beTree('(11,LL)(7,LLL)(8,R)(5,)(4,L)(13,RL)(2,LLR)(1,RRR)(4,RR)');
+		var front = 0,next = 1,n = 0;
+		var tree = [],ret = [];
+		tree[0] = root;
+		while(front < next) {
+				var node = tree[front++];
+				if(!node.child) {
+						return;
+				}
+				ret[n++] = node.value;
+				if(node.left !== null) {
+						tree[next++] = node.left;
+				}
+				if(node.right !== null) {
+						tree[next++] = node.right;
+				}
+		}
+		console.log(ret.join(' '));
+}
+bfs();