uploaded at 2023. 1. 31. 오후 11:19:55

programmers/삼각 달팽이/solution.java

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+// [문제 링크]: https://school.programmers.co.kr/learn/courses/30/lessons/68645
+
+import java.util.*;
+class Solution {
+    int max;
+    public int[] solution(int n) {
+        int cnt = 0, f = 0, idx = 0;
+        max = (n*(n+1))/2;
+        ArrayList<int[]> al = new ArrayList<>();
+        for(int a = 0; a < n; a++) al.add(new int[a+1]);
+        int a = -1, b = 0, state = 0;
+        while(cnt<max){
+            switch(state){
+                case 0: for(a++; a < n-f; a++) job(al,a,b,cnt++); a--; f++; state++; break;
+                case 1: for(b = f; b < n-2*(f-1); b++) job(al,a,b,cnt++); b--; state++; break;
+                case 2: for(a--,b--; b >= f; a--,b--) job(al,a,b,cnt++); a++;b++; state = 0; break;
+            }
+        } // for(int d = 0; d < n; d++) System.out.println(Arrays.toString(al.get(d)));
+        int[] answer = new int[max];
+        for(int d = 0; d < n; d++){
+            int[] temp = al.get(d);
+            for(int q = 0; q <= d; q++) answer[idx++] = temp[q];
+        }
+        return answer;
+    }
+    public void job(ArrayList<int[]> al, int a, int b, int data){
+        int[] temp = al.get(a);
+        temp[b] = data+1;
+    }
+}