Educational Codeforces Round 83 (Rated for Div. 2)E(区间DP)

#define HAVE_STRUCT_TIMESPEC
#include<bits/stdc++.h>
using namespace std;
int a[507];
int dp[507];
int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int n;
    cin>>n;
    for(int i=1;i<=n;++i)
        cin>>a[i];
    for(int i=1;i<=n;++i){
        stack<int>s;
        s.push(a[i]);
        dp[i]=dp[i-1]+1;
        for(int j=i-1;j;--j){
            int num=a[j];
            while(!s.empty()&&s.top()==num){
                s.pop();
                ++num;
            }
            s.push(num);
            dp[i]=min(dp[i],dp[j-1]+(int)s.size());
        }
    }
    cout<<dp[n];
    return 0;
}