Add functions rust

cpp/binpow-matrix.cpp

@@ -33,7 +33,7 @@ matrix2on2 mul(const matrix2on2 &first, const matrix2on2 &second) {
 const matrix2on2 IDENTITY_MATRIX = {1, 0, 0, 1};
 // See https://e-maxx.ru/algo/binary_pow
 matrix2on2 binpow(const matrix2on2 &a, int n) {
-  matrix2on2 result{};
+  matrix2on2 result;
   if (n == 0) {
     result = IDENTITY_MATRIX;
   } else if (n % 2 == 1) {

rust/binpow-matrix.rs

@@ -0,0 +1,57 @@
+// Copyright (c) 2022-2024 Yegor Bugayenko
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+type Matrix2x2 = [i32; 4];
+
+const IDENTITY_MATRIX: Matrix2x2 = [1, 0, 0, 1];
+
+fn mul(first: &Matrix2x2, second: &Matrix2x2) -> Matrix2x2 {
+    [
+        first[0] * second[0] + first[1] * second[2],
+        first[0] * second[1] + first[1] * second[3],
+        first[2] * second[0] + first[3] * second[2],
+        first[2] * second[1] + first[3] * second[3],
+    ]
+}
+
+fn binpow(a: &Matrix2x2, n: i32) -> Matrix2x2 {
+    if n == 0 {
+        IDENTITY_MATRIX
+    } else if n % 2 == 1 {
+        let temp = binpow(a, n - 1);
+        mul(&temp, a)
+    } else {
+        let b = binpow(a, n / 2);
+        mul(&b, &b)
+    }
+}
+
+fn calc(n: i32) -> i32 {
+    let n = n + 1;
+    let factor = [0, 1, 1, 1];
+    let multiplier = binpow(&factor, n);
+    let base = [0, 1, 0, 0];
+    mul(&base, &multiplier)[0]
+}
+
+fn main() {
+    let n = 10;
+    println!("Fibonacci number at position {}: {}", n, calc(n));
+}

rust/functions.rs

@@ -0,0 +1,53 @@
+// Copyright (c) 2022-2024 Yegor Bugayenko
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#[inline(never)]
+fn less(a: i32, b: i32) -> bool {
+    a < b
+}
+
+#[inline(never)]
+fn sub(a: i32, b: i32) -> i32 {
+    a - b
+}
+
+#[inline(never)]
+fn add(a: i32, b: i32) -> i32 {
+    a + b
+}
+
+#[inline(never)]
+fn fibo(x: i32) -> i32 {
+    if less(x, 2) {
+        1
+    } else {
+        add(fibo(sub(x, 1)), fibo(sub(x, 2)))
+    }
+}
+
+#[inline(never)]
+fn calc(x: i32) -> i32 {
+    fibo(x)
+}
+
+fn main() {
+    let x = 10;
+    println!("Fibonacci of {} is {}", x, calc(x));
+}