[이유진] 01.30 트리 문제 제출

solutions/yujin/0130/[문제28]트리순회.js

@@ -0,0 +1,29 @@
+const fs = require('fs');
+const input = fs.readFileSync('/dev/stdin').toString().trim().split('\n');
+
+const N = Number(input[0]);
+const tree = {};
+
+for (let i = 1; i <= N; i++) {
+  const [node, left, right] = input[i];
+  tree[node] = { left, right };
+}
+
+function preorder(node) {
+  if (node === '.') return '';
+  return node + preorder(tree[node].left) + preorder(tree[node].right);
+}
+
+function inorder(node) {
+  if (node === '.') return '';
+  return preorder(tree[node].left) + node + preorder(tree[node].right);
+}
+
+function postorder(node) {
+  if (node === '.') return '';
+  return postorder(tree[node].left) + postorder(tree[node].right) + node;
+}
+
+console.log(preorder('A'));
+console.log(inorder('A'));
+console.log(postorder('A'));

solutions/yujin/0130/[문제29]이진탐색트리구현.js

@@ -0,0 +1,61 @@
+class Node {
+  constructor(value) {
+    this.left = null;
+    this.right = null;
+    this.value = value;
+  }
+}
+
+class BST {
+  constructor() {
+    this.root = null;
+  }
+  insert(value) {
+    if (!this.root) {
+      this.root = new Node(value);
+      return;
+    } else {
+      let cur = this.root;
+      while (true) {
+        // 삽입 하려는 값이 현재 자식노드보다 작은 경우
+        if (value < cur) {
+          // 왼쪽으로 이동
+          if (cur.left) {
+            cur = cur.left;
+          } else {
+            cur.left = new Node(value);
+            break;
+          }
+        } else {
+          if (cur.right) {
+            cur = cur.right;
+          } else {
+            cur.right = new Node(value);
+            break;
+          }
+        }
+      }
+    }
+  }
+
+  search(value) {
+    let cur = this.root;
+    while (cur) {
+      if (cur.value === value) return true;
+      else if (cur.value < value) cur = cur.left;
+      else cur = cur.right;
+    }
+    return false;
+  }
+}
+
+function solution(lst, searchList) {
+  const bst = new BST();
+
+  for (const num of lst) {
+    bst.insert(num);
+  }
+  return searchList.map((v) => bst.search(v));
+}
+
+console.log(solution([5, 3, 8, 4, 2, 1, 7, 10], [1, 2, 5, 6]));

solutions/yujin/0130/[문제30]예상대진표.js

@@ -0,0 +1,11 @@
+function solution(n, a, b) {
+  let answer = 0;
+
+  while (a !== b) {
+    a = Math.ceil(a / 2);
+    b = Math.ceil(b / 2);
+    answer++;
+  }
+
+  return answer;
+}

solutions/yujin/0130/트리_순회.js

@@ -0,0 +1,48 @@
+function solution(arr) {
+  // 전위 순회
+  function preOrder(nodes, idx) {
+    const left = idx * 2 + 1;
+    const right = idx * 2 + 2;
+
+    if (idx < nodes.length) {
+      let ret = `${nodes[idx]}`;
+      ret += preOrder(nodes, left);
+      ret += preOrder(nodes, right);
+
+      return ret;
+    }
+    return '';
+  }
+
+  // 중위 순회
+  function inOrder(nodes, idx) {
+    const left = idx * 2 + 1;
+    const right = idx * 2 + 2;
+
+    if (idx < nodes.length) {
+      let ret = inOrder(nodes, left);
+      ret += `${nodes[idx]}`;
+      ret += inOrder(nodes, right);
+      return ret;
+    }
+    return '';
+  }
+
+  // 후위 순회
+  function postOrder(nodes, idx) {
+    let left = idx * 2 + 1;
+    let right = idx * 2 + 2;
+
+    if (idx < nodes.length) {
+      let ret = postOrder(nodes, left);
+      ret += postOrder(nodes, right);
+      ret += `${nodes[idx]}`;
+      return ret;
+    }
+    return '';
+  }
+
+  return [preOrder(arr, 0), inOrder(arr, 0), postOrder(arr, 0)];
+}
+
+console.log(solution([1, 2, 3, 4, 5, 6, 7]));