codeforces 358D

题目链接：http://codeforces.com/contest/358/problem/D

 

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>

using namespace std;

const int maxn = 3005;
int a[maxn],b[maxn],c[maxn];
int dp1[maxn],dp2[maxn];
int n;

int main()
{
     //freopen("E:\\acm\\input.txt","r",stdin);

     cin>>n;
     for(int i=1; i<=n; i++) cin>>a[i];
     for(int i=1; i<=n; i++) cin>>b[i];
     for(int i=1; i<=n; i++) cin>>c[i];

     dp2[n] = b[n];
     dp1[n] = a[n];
     for(int i=n-1; i>=1; i--)
     {
         dp1[i] = max(a[i]+dp2[i+1],b[i]+dp1[i+1]);
         dp2[i] = max(b[i]+dp2[i+1],c[i]+dp1[i+1]);
     }
     printf("%d\n",dp1[1]);
}