feat: 470_implement_rand10_using_rand7

470_implement_rand10_using_rand7/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "implement_rand10_using_rand7"
+version = "0.1.0"

470_implement_rand10_using_rand7/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "implement_rand10_using_rand7"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

470_implement_rand10_using_rand7/src/lib.rs

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+#[inline]
+fn rand7() -> i32 {
+    (std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap()
+        .as_nanos()
+        % 7) as i32
+}
+
+pub struct Solution;
+
+impl Solution {
+    pub fn rand10() -> i32 {
+        let mut rnd: i32;
+        loop {
+            rnd = (rand7() - 1) * 7 + rand7(); // [1, 49]
+
+            if rnd <= 40 {
+                break;
+            }
+        }
+        rnd % 10 + 1
+    }
+}