solve: 9613 GCD합

Author: 2ykwang

baekjoon/week_03/20_9613/9613.py

@@ -0,0 +1,23 @@
+import sys
+
+def input(): return sys.stdin.readline().rstrip()
+
+def GCD(a, b):
+    while b:
+        a, b = b, a % b
+    return a
+
+for _ in range(int(input())):
+
+    nums = list(map(int, input().split()[1:]))
+
+    nums_count = len(nums)
+
+    answer = 0
+
+    # combination
+    for i in range(nums_count):
+        for j in range(i+1, nums_count):
+            answer += GCD(nums[i], nums[j])
+
+    print(answer)

baekjoon/week_03/20_9613/README.md

@@ -2,13 +2,44 @@
 file: "9613.py"
 name: "GCD 합"
 src: "https://www.acmicpc.net/problem/9613"
-tags: 
+tags:
   - 유클리드 호제법
   - 수학
   - 정수론
-done: false
+done: true
 draft: false
 level: 8
 difficulty: "Silver III"
 date: 2021-11-02
 ---
+
+# GCD 합
+
+## 정답 코드
+
+```python
+import sys
+
+def input(): return sys.stdin.readline().rstrip()
+
+def GCD(a, b):
+    while b:
+        a, b = b, a % b
+    return a
+
+for _ in range(int(input())):
+
+    # 가장 앞 원소는 생략한다.
+    nums = list(map(int, input().split()[1:]))
+
+    nums_count = len(nums)
+
+    answer = 0
+
+    # combination
+    for i in range(nums_count):
+        for j in range(i+1, nums_count):
+            answer += GCD(nums[i], nums[j])
+
+    print(answer)
+```