From dee2ba0a7d0665fbe209b63f3651d2f29d9aa913 Mon Sep 17 00:00:00 2001
From: songyc macbook <gitea@gitea>
Date: Thu, 12 Mar 2026 20:57:32 +0900
Subject: [PATCH] baekjoon 20260311-12

---
 code_study/Baekjoon/python/15439.py  |  1 +
 code_study/Baekjoon/swift/9527.swift | 33 ++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 code_study/Baekjoon/python/15439.py
 create mode 100644 code_study/Baekjoon/swift/9527.swift

diff --git a/code_study/Baekjoon/python/15439.py b/code_study/Baekjoon/python/15439.py
new file mode 100644
index 0000000..7b20822
--- /dev/null
+++ b/code_study/Baekjoon/python/15439.py
@@ -0,0 +1 @@
+print((lambda x: x*(x-1))(int(input())))
\ No newline at end of file
diff --git a/code_study/Baekjoon/swift/9527.swift b/code_study/Baekjoon/swift/9527.swift
new file mode 100644
index 0000000..1ef1c07
--- /dev/null
+++ b/code_study/Baekjoon/swift/9527.swift
@@ -0,0 +1,33 @@
+var dp: [Int64] = Array(repeating: 0, count: 55)
+
+for n in 1...54 {
+    dp[n] = 2*dp[n-1] + (1 << (n-1))
+}
+
+func countOne(_ N: Int64) -> Int64 {
+    var res: Int64 = 0
+    var n: Int64 = N
+    
+    for i in stride(from: 54, to: 0, by: -1) {
+        let LSB: Int64 = (1 << (i-1)) & n
+        
+        if LSB != 0{
+            res += dp[i-1]
+            res += n - (1 << (i-1)) + 1
+        }
+        
+        n &= ((1 << (i-1)) - 1)
+    }
+    
+    return res
+}
+
+func main() {
+    guard let input = readLine() else { return }
+    let nums: [Int64] = input.split(separator: " ").compactMap{Int64($0)}
+    
+    let ans: Int64 = countOne(nums[1]) - countOne(nums[0]-1)
+    print(ans)
+}
+
+main()