Finished abc050

atcoder/beginner_contests/abc050/src/bin/d.rs

@@ -1,3 +1,38 @@
-fn main() {
+use std::collections::HashMap;
-    unimplemented!();
+
+use proconio::input;
+
+const MOD: u128 = 1000000007;
+
+fn solve(n: u128, memory: &mut HashMap<u128, u128>) -> u128 {
+    if n == 0 {
+        return 1;
+    } else if n == 1 {
+        return 2;
+    }
+
+    if let Some(res) = memory.get(&n) {
+        return *res;
+    }
+    
+    if n % 2 == 0 {
+        let res = (2 * solve(n / 2 - 1, memory) + solve(n / 2, memory)) % MOD;
+        memory.insert(n, res);
+        return res;
+    } else {
+        let res = (2 * solve(n / 2, memory) + solve(n / 2 - 1, memory)) % MOD;
+        memory.insert(n, res);
+        return res;
+    }
+}
+
+fn main() {
+    input! {
+        n: u128,
+    };
+
+    let mut memory = HashMap::new();
+    let result = solve(n, &mut memory);
+
+    println!("{}", result);
 }