Node.js) 백준 1991번: 트리 순회

https://www.acmicpc.net/problem/1991

1991번: 트리 순회

 

const fs = require('fs');
const [_,...input] = fs.readFileSync("./dev/stdin").toString().trim().split("\n");

let tree = {};

input.forEach(v=>{
  const data = v[0];
  const left = v[2]=='.'? null : v[2];
  const right = v[4]=='.'? null : v[4];

  tree[data] = {left,right}
})

let answer = ['','',''];

function preOrder(node){ 
  if(( tree[node] != null)){ 
    answer[0]+=node;
    preOrder( tree[node].left);
    preOrder( tree[node].right);
  }
}


function inOrder(node){ 
  if(tree[node] != null){ 
    inOrder(tree[node].left);
    answer[1]+=node;
    inOrder(tree[node].right);
  }
}

function postOrder(node){ 
  if((tree[node]!= null)){ 
    postOrder(tree[node].left);
    postOrder(tree[node].right);
    answer[2]+=node;
  }
}



preOrder('A')
inOrder('A')
postOrder('A')

console.log(answer.join('\n'))