1018

djs02027 · djs02027 · commit 69fc943693e9 · 2022-10-18T15:43:47.000+09:00
diff --git a/.idea/modules.xml b/.idea/modules.xml
diff --git a/BOJ/gold/BOJ17425/BOJ17425.iml b/BOJ/gold/BOJ17425/BOJ17425.iml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
diff --git a/BOJ/gold/BOJ17425/src/Main.java b/BOJ/gold/BOJ17425/src/Main.java
@@ -0,0 +1,35 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+
+public class Main {
+    static final int MAX = 1000001;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringBuilder sb =new StringBuilder();
+        int T = Integer.parseInt(br.readLine());
+        long[] dp = new long[MAX];
+        //1은 모든수의 약수이므로
+        Arrays.fill(dp, 1);
+        for (int i = 2; i < MAX; i++) {
+            for (int j = 1; j * i < MAX; j++) {
+                //i*j의 약수인 i를 더해준다.
+                //4의 약수 2*2, 4*1 등 124가 더해짐
+                dp[i * j] += i;
+            }
+            //누적합을 만들기 위해 진행
+            dp[i] = dp[i] + dp[i - 1];
+        }
+        //sout보다는 stringbulider를 활용해야 시간 초과가 안남
+        for (int i = 0; i < T; i++) {
+
+            int N = Integer.parseInt(br.readLine());
+            sb.append(dp[N]+"\n");
+        }
+        System.out.println(sb);
+
+    }
+}
