2020 카카오 블라인드 프로그래머스 - 길 찾기 게임

https://programmers.co.kr/learn/courses/30/lessons/42892

코딩테스트 연습 - 길 찾기 게임

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import java.util.*; class Solution {     class Tree{         Tree right;         Tree left;         int x=0;         int y=0;         int index=0;         Tree(int x,int y,int index){             this.x=x;             this.y=y;             this.index=index;         }     }     public int[][] solution(int[][] nodeinfo) {        int[][] answer =new int[2][nodeinfo.length];         int index=0;         Tree[] trees= new Tree[nodeinfo.length];         for (int i = 0; i < nodeinfo.length; i++) {             trees[i]=new Tree(nodeinfo[i][0],nodeinfo[i][1],++index);         }         Arrays.sort(trees, new Comparator<Tree>() {             @Override             public int compare(Tree o1, Tree o2) {                 int x1=o1.x;int x2=o2.x;int y1=o1.y;int y2=o2.y;                 if(y1<y2) return 1;                 else if(y1>y2) return -1;                 else if(y1==y2){                     if(x1>x2) return 1;                     else return -1;                 }                 return 0;             }         });         Tree root=trees[0];         for(int i=1;i<trees.length;i++){             connect_Tree(root,trees[i]);         }           ArrayList<Integer> list = new ArrayList<>();         preOrder(root,list);         for (int i = 0; i < list.size(); i++) {             answer[0][i]=list.get(i);         }         System.out.println();         list.clear();         postOrder(root,list);         for(int i=0;i<list.size();i++){             answer[1][i]=list.get(i);         }           return answer;     }         public static void connect_Tree(Tree root,Tree node){         if(root.x>node.x){             if(root.left!=null){                 connect_Tree(root.left,node);             }else{                 root.left=node;             }         }else{             if (root.right != null) {                 connect_Tree(root.right,node);             }else{                 root.right=node;             }         }     }       public void preOrder(Tree root, ArrayList<Integer> list) {         list.add(root.index);         if (root.left != null) {             preOrder(root.left,list);         }         if (root.right != null) {             preOrder(root.right,list);         }     }       public void postOrder(Tree root, ArrayList<Integer> list) {         if (root.left != null) {             postOrder(root.left,list);         }         if (root.right != null) {             postOrder(root.right,list);         }         list.add(root.index);     } }

cs

트리 구조를 만들어주면 끝난다.

그걸 생각못하고 처음에 너무 돌아 갔따.... 정답률 보니 트리 까먹어서 생각못한 사람들이 많은 것 같다.

기초를 잊지말자!