new file: P3146.cpp

P3146.cpp

@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+#define int long long
+using namespace std;
+int n;
+int a[250];
+int f[250][250]; // l, r
+signed main() {
+    int ans = 0;
+    scanf("%lld", &n);
+    for (int i = 1; i <= n; ++i) {
+        scanf("%lld", &a[i]);
+        f[i][i] = a[i];
+        ans = max(ans, a[i]);
+    }
+    for (int len = 2; len <= n; ++len) {
+        for (int end = len; end <= n; ++end) {
+            int begin = end - len + 1;
+            for (int i = begin; i <= end; i++) {
+                if (f[begin][i] == f[i + 1][end] && f[begin][i] != 0)
+                    f[begin][end] = max(f[begin][end], f[begin][i] + 1);
+            }
+            ans = max(ans, f[begin][end]);
+        }
+    }
+    printf("%lld\n", ans);
+    return 0;
+}