E - Multiplication Puzzle

 #include <iostream>
 #include <algorithm>
 #include <cstring>
 #include <cstdio>
 #include <string>
 #include <map>
 #include <cmath>
 #include <vector>

 #define Faster ios::sync_with_stdio(false),cin.tie(0)
 #define Read freopen("in.txt","r",stdin),freopen("out.txt","w",stdout)
 #define Close fclose(stdin),fclose(stdout)
 const int maxn = ;
 using namespace std;
 const int MOD = 1e9+;
 typedef long long ll;

 #define INF 100000000

 int a[maxn];
 int dp[maxn][maxn];

 int main(){
     Faster;
     int n;
     cin >> n;
     for(int i = ;i <= n;i++){
         cin >> a[i];
     }
     memset(dp, , sizeof(dp));
     for(int l = ;l < n;l++){    //长度从2开始
         for(int i = ;i+l <= n+;i++){
             int j = i+l-;
             dp[i][j] = INF;
             for(int k = i;k < j;k++){    //枚举中点
                 dp[i][j] = min(dp[i][j], dp[i][k]+dp[k+][j] + a[i-]*a[k]*a[j]);
             }
         }
     }
     cout << dp[][n] << endl;
     return ;
 }