Solve Problem 1011.

gnidoc327 · Jan 13, 2019 · 6e19939 · 6e19939
1 parent e029384
commit 6e19939
Showing 1 changed file with 21 additions and 52 deletions.
diff --git a/src/step_by_step/step8/Problem1011/Main.java b/src/step_by_step/step8/Problem1011/Main.java
@@ -3,70 +3,39 @@
 package step_by_step.step8.Problem1011;
 
 
-import java.util.ArrayList;
-import java.util.Date;
 import java.util.Scanner;
 
 public class Main {
-    static ArrayList<Integer> arrayList = new ArrayList<>();
-
     public static void main(String[] args) {
-        Date start = new Date();
-
         Scanner sc = new Scanner(System.in);
-//        int t = sc.nextInt();
-//        int[][] input = new int[t][2];
-        int t = 3;
-        int[][] input = {
-                {0, (int) Math.pow(2, 31)}//, {1, 5}, {45, 50}
-        };
+        int t = sc.nextInt();
+        int[][] input = new int[t][2];
 
-//        for (int i = 0; i < t; i++) {
-//            input[i][0] = sc.nextInt();
-//            input[i][1] = sc.nextInt();
-//        }
-
-        int maxN = 0;
-        for (int[] xy : input) {
-            if (xy[1] - xy[0] > maxN) {
-                maxN = xy[1] - xy[0];
-            }
+        for (int i = 0; i < t; i++) {
+            input[i][0] = sc.nextInt();
+            input[i][1] = sc.nextInt();
         }
 
-        calc(maxN);
-
         for (int i = 0; i < t; i++) {
-            int distance = input[i][1] - input[i][0];
-            for (int j = 0; j < arrayList.size(); j++) {
-                if (arrayList.get(j) >= distance) {
-                    System.out.println(j + 1);
-                    break;
-                }
-            }
+            calc(input[i][1] - input[i][0]);
         }
-
-        System.out.println("time : " + (new Date().getTime() - start.getTime()));
     }
-    // f( 횟수 ) = 최대 거리
-    // f( 2n - 1 ) = nn
-    // f( 2n) ) = n(n+1)
-    static void calc(int maxDistance) {
-        arrayList.add(1);
-        arrayList.add(2);
 
-        int i = 3;
-        while (true) {
-            if (i % 2 == 0) {
-                int j = i / 2;
-                arrayList.add(j * (j + 1));
-            } else {
-                int j = (i + 1) / 2;
-                arrayList.add(j * j);
-            }
-            if (arrayList.get(arrayList.size() - 1) > maxDistance) {
-                return;
-            }
-            i++;
+    static void calc(int distance) {
+        if (distance <= 2) {
+            System.out.println(distance);
+            return;
         }
+        int n = (int) Math.sqrt(distance);
+        int result;
+        if (distance == n * n) {
+            result = 2 * n - 1;
+        } else if (distance <= n * (n + 1)) {
+            result = 2 * n;
+        } else {
+            result = 2 * (n + 1) - 1;
+        }
+
+        System.out.println(result);
     }
 }