20251102 baekjoon

code_study/Baekjoon/python/13172.py

@@ -0,0 +1,25 @@
+MOD = 1000000007
+
+def power(x,n) :
+    if n==0 :
+        return 1
+    if n==1 :
+        return x%MOD
+    
+    half = power(x,n//2)
+    result = (half*half)%MOD
+    
+    if n%2==1 :
+        result = (result*x)%MOD
+    
+    return result
+
+inverse_element_MOD = lambda x: power(x, MOD-2)
+expect_value = lambda a, b : (a*inverse_element_MOD(b))%MOD
+
+result = 0
+for _ in range(int(input())) :
+    S, N = map(int, input().split())
+    result = (result + expect_value(N,S))%MOD
+
+print(result)

code_study/Baekjoon/python/7287.py

@@ -0,0 +1 @@
+print('\n'.join((["285", "syc725"])))

code_study/Baekjoon/swift/11444.swift

@@ -0,0 +1,35 @@
+let Mod: Int64 = 1000000007
+
+func matrix_multiply_2by2(_ A: [[Int64]], _ B: [[Int64]]) -> [[Int64]] {
+    var result = Array(repeating: Array(repeating: Int64(0), count: 4), count: 4)
+    
+    result[0][0] = (A[0][0]*B[0][0] + A[0][1]*B[1][0])%Mod
+    result[0][1] = (A[0][0]*B[0][1] + A[0][1]*B[1][1])%Mod
+    result[1][0] = (A[1][0]*B[0][0] + A[1][1]*B[1][0])%Mod
+    result[1][1] = (A[1][0]*B[0][1] + A[1][1]*B[1][1])%Mod
+    
+    return result
+}
+
+func power_matrix_2by2(_ A: [[Int64]], exponetioal n: Int64) -> [[Int64]] {
+    if n == 0 {
+        return [[1,0],[0,1]]
+    }
+    
+    if n == 1 {
+        return A
+    }
+    
+    let half = power_matrix_2by2(A, exponetioal: n/2)
+    let result = matrix_multiply_2by2(half, half)
+    
+    if n%2 == 1 {
+        return matrix_multiply_2by2(result, A)
+    }
+    
+    return result
+}
+
+if let n = Int64(readLine() ?? "") {
+    print(power_matrix_2by2([[1,1],[1,0]], exponetioal: n)[1][0])
+}