past16-open j

cargo-atcoder-1.70.0/contests/past16-open/src/bin/j.rs

@@ -1,10 +1,58 @@
-use proconio::{input, marker::Usize1};
+use proconio::input;
+
+fn divisors(n: usize) -> Vec<usize> {
+    let mut d = vec![];
+    for i in 1.. {
+        if i * i > n {
+            break;
+        }
+        if n % i == 0 {
+            d.push(i);
+            if i != n / i {
+                d.push(n / i);
+            }
+        }
+    }
+    d.sort();
+    d
+}
+
+fn gcd(n: usize, m: usize) -> usize {
+    if m == 0 {
+        n
+    } else {
+        gcd(m, n % m)
+    }
+}
 
 fn main() {
     input! {
         n: usize,
-        a: [Usize1; n],
+        k: usize,
+        a: [usize; k],
     };
-    let ans = n - a.len();
-    println!("{}", ans);
+
+    let mut b = vec![];
+    let mut prev = a[0];
+    for a_i in a.iter().copied().skip(1) {
+        b.push(a_i - prev);
+        prev = a_i;
+    }
+
+    let mut g = gcd(b[0], if b.len() == 1 { b[0] } else { b[1] });
+    for b_i in b {
+        g = gcd(g, b_i);
+    }
+
+    let mut ans = vec![];
+    for d in divisors(g) {
+        if (n - 1) * d >= a[k - 1] - a[0] {
+            ans.push(d);
+        }
+    }
+
+    println!("{}", ans.len());
+    for a in ans {
+        println!("{}", a);
+    }
 }