[区间dp] poj 1651 Multiplication Puzzle

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<algorithm>
using namespace std;
const int MAXN = 105;
const int INF = 0x1f1f1f1f;
int n;
int a[MAXN];
int dp[MAXN][MAXN];
int dfs(int l,int r)
{
if(dp[l][r]<INF) return dp[l][r];
if(r-l<2) return 0;
if(r-l==2) return dp[l][r]=a[l]*a[l+1]*a[r];
int ans=INF;
for(int i=l+1;i<r;i++)
ans=min(ans,dfs(l,i)+dfs(i,r)+a[l]*a[i]*a[r]);
return dp[l][r]=ans;
}
int main()
{
cin>>n;
for(int i=0;i<n;i++) cin>>a[i];
memset(dp,0x1f,sizeof dp);
cout<<dfs(0,n-1)<<endl;;
//cout<<dp[0][2]<<endl;
return 0;
}