updated at 2022. 12. 30. 오전 12:59:17

programmers/마법의 엘리베이터/solution.java

@@ -1,18 +1,32 @@
 // [문제 링크]: https://school.programmers.co.kr/learn/courses/30/lessons/148653
 
+import java.util.*;
+import java.util.stream.*;
 class Solution {
     public int solution(int storey) {
-        int answer = 0;
-        while (storey != 0) {
-            int upperNumber = (storey %100)/10;
-            int number = storey % 10;
-            if (number > 5 || number == 5 && upperNumber>=5) {
-                storey += 10;
-                answer += (10 - number);
+        int answer = 0, temp = 0;
+        int max = (int)Math.round(Math.log10(storey));
+        //System.out.println(max);
+        temp = storey;
+        boolean up = false;
+        for(int a = 0; a <= max; a++){
+            int target = (int)(Math.round(temp/Math.pow(10,a))*Math.pow(10,a));
+            int[] ar = Stream.of(String.valueOf(target).split("")).mapToInt(Integer::parseInt).toArray();
+            int tt = (ar.length-a>0)?ar[ar.length-1-a]:0;
+            //System.out.println(target+"tg"+temp+" "+((tt<5)?tt:10-tt)*(int)Math.pow(10,a));
+            if(ar.length-1-a > 0 && ar[ar.length-2-a]>=5 && tt == 5) up = true;
+			else up = false;
+            if(tt<5 || !up && tt == 5){
+                temp-=tt*Math.pow(10,a);
+                answer+=tt;
+                //System.out.println("-");
             } else{
-                answer += number;
+                temp+=(10-tt)*Math.pow(10,a);
+                answer+=10-tt;
+                //System.out.println("+");
             }
-            storey = storey / 10;
+            if(temp == 0) break;
+            //if(temp<0) System.out.println("error");
         }
         return answer;
     }