@[心余无痕](/user/305002) 把 dp 数组的初值改成 $-1$，因为数组中可能有大量的 $0$，导致重复搜索。
by Alan_Zhao @ 2021-08-24 21:34:15
@[Alan_Zhao](/user/225625) 好像还是T
by StormyEpisode @ 2021-08-24 21:36:50
@[心余无痕](/user/305002) 我改完就过了，你应该改错了
by Alan_Zhao @ 2021-08-24 21:39:08
@[心余无痕](/user/305002)
```cpp
#include <bits/stdc++.h>
using namespace std;
const int N = 300;
int n, a[N], dp[N][N];
// 这里考虑只转移能够合并的
int solve(int L, int R) {
if(dp[L][R]!=-1) return dp[L][R];
if(L == R) return a[L];
int res = 0;
for(int i = L; i < R; i ++ ) {
int s1 = solve(L, i), s2 = solve(i + 1, R);
if(!s1 || !s2) continue;
if(s1 == s2) res = max(res, s1 + 1);
}
return dp[L][R] = res;
}
int main() {
memset(dp,-1,sizeof dp);
cin >> n;
for(int i = 1; i <= n; i ++ ) cin >> a[i];
int res = 0;
solve(1, n);
for(int i = 1; i <= n; i ++ )
for(int j = i; j <= n; j ++ ) {
res = max(res, dp[i][j]);
#ifdef debug
cout << "[" << i << ", " << j << "]: " << solve(i, j) << endl;
#endif
}
cout << res << endl;
return 0;
}
```
by Alan_Zhao @ 2021-08-24 21:39:51
好吧我太菜了
by StormyEpisode @ 2021-08-24 21:40:08
我NC写了个`if dp[l, r] > 0 return`
by StormyEpisode @ 2021-08-24 21:43:06