poj 1651Multiplication Puzzle dp

原来我是真的水。。裸矩阵连乘我怎么还想着用贪心呢。

#include<cstdio>#include<algorithm>#include<cstring>//#include<cmath>#define fo(i,a,b) for(int i=a;i<=b;i++)#define fd(i,a,b) for(int i=a;i>=b;i--)using namespace std;typedef long long ll;const int N=1e3;const int inf=1e9;int f[N][N],a[N],n;int main(){    scanf("%d",&n);    fo(i,1,n)scanf("%d",&a[i]);    fd(i,n,1)    {        fo(j,i+2,n)        {            f[i][j]=inf;            fo(k,i+1,j-1)            f[i][j]=min(f[i][j],f[i][k]+f[k][j]+a[i]*a[j]*a[k]);        }    }    printf("%d\n",f[1][n]); }