SXCPC2018 nucoj2007 和Mengjiji一起攻克难关

#include <algorithm>
#include <iostream>
#include <cstdio>
using namespace std;
typedef long long ll;
int n, a[2005];
ll dp[2005][2005];
int main(){
    cin>>n;
    for(int i=1; i<=n; i++)
        scanf("%d", &a[i]);
    dp[2][0] = abs(a[2]-a[1]);
    for(int i=3; i<=n; i++)
        for(int j=0; j<i; j++){
            if(j==i-1){
                dp[i][j] = dp[i-1][0];
                for(int k=1; k<=i-2; k++)
                    dp[i][j] = min(dp[i][j], dp[j][k]+abs(a[k]-a[i]));
            }
            else    dp[i][j] = dp[i-1][j] + abs(a[i] - a[i-1]);
        }
    ll ans=0x3f3f3f3f3f3f3f3f;
    for(int i=0; i<n; i++)
        ans = min(ans, dp[n][i]);
    cout<<ans<<endl;
    return 0;
}