diff --git a/tessoku-book/src/bin/c18.rs b/tessoku-book/src/bin/c18.rs
index 2a9506c8..376df1bf 100644
--- a/tessoku-book/src/bin/c18.rs
+++ b/tessoku-book/src/bin/c18.rs
@@ -1,10 +1,39 @@
-use proconio::{input, marker::Usize1};
+use proconio::input;
 
 fn main() {
     input! {
         n: usize,
-        a: [Usize1; n],
+        a: [usize; 2 * n],
     };
-    let ans = n - a.len();
+    let inf = 1_usize << 60;
+    let mut dp = vec![vec![inf; 2 * n]; 2 * n];
+    let d = |a: usize, b: usize| -> usize {
+        if a > b {
+            a - b
+        } else {
+            b - a
+        }
+    };
+    for l in 0..2 * n {
+        let r = l + 1;
+        if r >= 2 * n {
+            continue;
+        }
+        dp[l][r] = d(a[l], a[r]);
+    }
+    for len in (3..=2 * n).step_by(2) {
+        for l in 0..2 * n {
+            let r = l + len;
+            if r >= 2 * n {
+                continue;
+            }
+            let mut min = dp[l + 1][r - 1] + d(a[l], a[r]);
+            for m in l..r {
+                min = min.min(dp[l][m] + dp[m + 1][r]);
+            }
+            dp[l][r] = min;
+        }
+    }
+    let ans = dp[0][2 * n - 1];
     println!("{}", ans);
 }