complete 11778.rs

storage/zeta/rs/completed/11778.rs

@@ -0,0 +1,69 @@
+use std::io::stdin;
+
+const MOD: u64 = 1_000_000_007;
+
+struct sqmat2 {
+    data: [[u64; 2]; 2],
+}
+
+impl sqmat2 {
+    fn mul(&self, other: &sqmat2) -> sqmat2 {
+        let mut res = sqmat2 { data: [[0; 2]; 2] };
+        for i in 0..2 {
+            for j in 0..2 {
+                for k in 0..2 {
+                    res.data[i][j] =
+                        (res.data[i][j] + self.data[i][k] * other.data[k][j] % MOD) % MOD;
+                }
+            }
+        }
+        res
+    }
+}
+
+fn gcd(a: u64, b: u64) -> u64 {
+    if b == 0 {
+        return a;
+    }
+    gcd(b, a % b)
+}
+
+fn fib(mut n: u64) -> u64 {
+    if n == 0 {
+        return 0;
+    }
+    let mut f = sqmat2 {
+        data: [[1, 0], [0, 1]],
+    };
+    let mut curr = sqmat2 {
+        data: [[1, 1], [1, 0]],
+    };
+    while n > 0 {
+        if n & 1 == 1 {
+            f = f.mul(&curr);
+        }
+        n >>= 1;
+        curr = curr.mul(&curr);
+    }
+
+    f.data[0][1] % MOD
+}
+
+fn gcd_fib(n: u64, m: u64) -> u64 {
+    if m == 0 {
+        return n;
+    }
+    fib(gcd(m, n % m))
+}
+
+fn main() {
+    let mut line = String::new();
+    stdin().read_line(&mut line).unwrap();
+
+    let mut iter = line.split(' ').map(|x| x.trim().parse::<u64>().unwrap());
+
+    let n = iter.next().unwrap();
+    let m = iter.next().unwrap();
+
+    println!("{}", gcd_fib(n, m));
+}