047

047/main.rs

@@ -0,0 +1,66 @@
+use std::collections::HashSet;
+
+type HS = HashSet<u32>;
+
+fn er() -> HS {
+    let mut nums = Vec::new();
+    let size = 1_000;
+    for n in 0..size+1 { nums.push(true); }
+    let mut p = 1;
+    loop {
+        let mut found = false;
+        for i in p+1..size {
+            if nums[i] {
+                found = true;
+                p = i;
+                break;
+            }
+        }
+        if !found { break; }
+        for i in (2 * p .. size).step_by(p) {
+            nums[i] = false;
+        }
+    }
+    let mut res = HashSet::new();
+    for i in 2..size {
+        if nums[i] { res.insert(i as u32); }
+    }
+    return res;
+}
+
+fn cj(n: u32, ps: &HS) -> u64 {
+    let mut nn = n;
+    let mut pc = 0;
+
+        for p in ps.iter() {
+            if nn == 1 {
+                break;
+            }
+            if nn % p == 0 {
+                pc += 1;
+                while nn % p == 0 {
+                    nn /= p;
+                }
+            }
+        }
+    
+    return pc;
+}
+
+fn main() {
+    let ps = er();
+    for n in 2..10_00000 {
+        let mut found = true;
+        for k in 0..=3 {
+            let t = cj(n + k, &ps);
+            if t != 4 {
+                found = false;
+                break;
+            }
+        }
+        if found {
+            println!("{}", n);
+            break;
+        }
+    }
+}