LPS HDOJ 4745 Two Rabbits

题目传送门

 /*
     题意：一只兔子顺时针跳，另一只逆时针跳，跳石头权值相等而且不能越过起点
     LPS：这道就是LPS的应用，把环倍增成链，套一下LPS，然而并不能理解dp[i][i+n-2] + 1，看别人的解题报告吧，以后来补(玩游戏)
 　　详细解释 */
 /************************************************
 * Author        :Running_Time
 * Created Time  :2015-8-8 16:57:23
 * File Name     :HDOJ_4747_LPS.cpp
  ************************************************/

 #include <cstdio>
 #include <algorithm>
 #include <iostream>
 #include <sstream>
 #include <cstring>
 #include <cmath>
 #include <string>
 #include <vector>
 #include <queue>
 #include <deque>
 #include <stack>
 #include <list>
 #include <map>
 #include <set>
 #include <bitset>
 #include <cstdlib>
 #include <ctime>
 using namespace std;

 #define lson l, mid, rt << 1
 #define rson mid + 1, r, rt << 1 | 1
 typedef long long ll;
 const int MAXN = 2e3 + ;
 const int INF = 0x3f3f3f3f;
 const int MOD = 1e9 + ;
 int a[MAXN], dp[MAXN][MAXN];

 int main(void)    {     //HDOJ 4745 Two Rabbits
     int n;
     while (scanf ("%d", &n) == )   {
         if (!n) break;
         for (int i=; i<=n; ++i)    {
             scanf ("%d", &a[i]);
             a[i+n] = a[i];
         }
         memset (dp, , sizeof (dp));
         for (int i=; i<=*n; ++i)  dp[i][i] = ;
         for (int i=; i<*n; ++i)    {
             for (int j=; j+i-<=*n; ++j)    {
                 if (a[j] == a[j+i-]) dp[j][j+i-] = dp[j+][j+i-] + ;
                 else    {
                     dp[j][j+i-] = max (dp[j+][j+i-], dp[j][j+i-]);
                 }
             }
         }
         int ans = ;
         for (int i=; i<=n; ++i)    {
             ans = max (ans, dp[i][i+n-]);
             ans = max (ans, dp[i][i+n-] + );
         }
         printf ("%d\n", ans);
     }

     return ;
 }