From 7713382709b92e2c917f0eebbae5b5934d30334a Mon Sep 17 00:00:00 2001
From: sangge <2251250136@qq.com>
Date: Sun, 31 Aug 2025 16:33:01 +0800
Subject: [PATCH] feat: finish 22

---
 problems/p22/Cargo.toml  |  8 ++++++++
 problems/p22/src/main.rs | 42 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 problems/p22/Cargo.toml
 create mode 100644 problems/p22/src/main.rs

diff --git a/problems/p22/Cargo.toml b/problems/p22/Cargo.toml
new file mode 100644
index 0000000..7f4cd2a
--- /dev/null
+++ b/problems/p22/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "p22"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+common = { path = "../../common/" }
+rand = { workspace = true }
diff --git a/problems/p22/src/main.rs b/problems/p22/src/main.rs
new file mode 100644
index 0000000..8e1e611
--- /dev/null
+++ b/problems/p22/src/main.rs
@@ -0,0 +1,42 @@
+use common::MT19937;
+use rand::{prelude::*, rng};
+use std::thread::sleep;
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+fn get_sec() -> u32 {
+    let now = SystemTime::now();
+    let duration_since_epoch = now.duration_since(UNIX_EPOCH).expect("Time went backwards"); // Handle potential errors if system time is earlier than epoch.
+
+    let unix_timestamp_seconds = duration_since_epoch.as_secs();
+    // overflow at 2038
+    unix_timestamp_seconds as u32
+}
+
+fn crack(rand_num: u32) -> u32 {
+    let now = get_sec();
+    for i in 5..20 {
+        let mut mt19937 = MT19937::new(now - i);
+        let result = mt19937.extract_number();
+        if rand_num == result {
+            return now - i;
+        }
+    }
+    0
+}
+
+fn main() {
+    let mut rng = rng();
+    let sleep_time: u64 = rng.random_range(5..20);
+    sleep(Duration::from_secs(sleep_time));
+    let seed = get_sec();
+    let mut mt19937 = MT19937::new(seed);
+    let sleep_time: u64 = rng.random_range(5..20);
+    sleep(Duration::from_secs(sleep_time));
+    let result = mt19937.extract_number();
+    let cracked = crack(result);
+    if cracked == seed {
+        println!("cracked");
+    } else {
+        println!("failed");
+    }
+}