HDU 4597 Play Game （DP，記憶化搜索）

Play Game

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)
Total Submission(s): 24    Accepted Submission(s): 18

Problem Description

Alice and Bob are playing a game. There are two piles of cards. There are N cards in each pile, and each card has a score. They take turns to pick up the top or bottom card from either pile, and the score of the card will be added to his total score. Alice and Bob are both clever enough, and will pick up cards to get as many scores as possible. Do you know how many scores can Alice get if he picks up first?

 

 

Input

The first line contains an integer T (T≤100), indicating the number of cases. 
Each case contains 3 lines. The first line is the N (N≤20). The second line contains N integer a _i (1≤a _i≤10000). The third line contains N integer b _i (1≤b _i≤10000).

 

 

Output

For each case, output an integer, indicating the most score Alice can get.

 

 

Sample Input

2 1 23 53 3 10 100 20 2 4 3

 

 

Sample Output

53 105

 

 

Source

2013 ACM-ICPC吉林通化全國邀請賽——題目重現

 

 

Recommend

liuyiding

 

 

 

 

 

只有每種狀況記憶化搜索下就能夠了

 

 

 1 /* ***********************************************
 2 Author        :kuangbin
 3 Created Time  :2013/8/24 12:37:04
 4 File Name     :F:\2013ACM練習\比賽練習\2013通化邀請賽\1008.cpp
 5 ************************************************ */
 6 
 7 #include <stdio.h>
 8 #include <string.h>
 9 #include <iostream>
10 #include <algorithm>
11 #include <vector>
12 #include <queue>
13 #include <set>
14 #include <map>
15 #include <string>
16 #include <math.h>
17 #include <stdlib.h>
18 #include <time.h>
19 using namespace std;
20 int a[30],b[30];
21 int sum1[30];
22 int sum2[30];
23 int dp[30][30][30][30];
24 int solve(int l1,int r1,int l2,int r2)
25 {
26     if(dp[l1][r1][l2][r2] != -1)return dp[l1][r1][l2][r2];
27     if(l1 > r1 && l2 > r2)
28         return dp[l1][r1][l2][r2] = 0;
29     int ans = 0;
30     int sum = 0;
31     if(l1 <= r1)
32         sum += sum1[r1] - sum1[l1-1];
33     if(l2 <= r2)
34         sum += sum2[r2] - sum2[l2-1];
35     if(l1 <= r1)
36     {
37         ans = max(ans,sum - solve(l1+1,r1,l2,r2));
38         ans = max(ans,sum - solve(l1,r1-1,l2,r2));
39     }
40     if(l2 <= r2)
41     {
42         ans = max(ans,sum - solve(l1,r1,l2+1,r2));
43         ans = max(ans,sum - solve(l1,r1,l2,r2-1));
44     }
45     return dp[l1][r1][l2][r2] = ans;
46 }
47 int main()
48 {
49     //freopen("in.txt","r",stdin);
50     //freopen("out.txt","w",stdout);
51     int n;
52     int T;
53     scanf("%d",&T);
54     while(T--)
55     {
56         scanf("%d",&n);
57         sum1[0] = sum2[0] = 0;
58         for(int i = 1;i <= n;i++)
59         {
60             scanf("%d",&a[i]);
61             sum1[i] = sum1[i-1] + a[i];
62         }
63         for(int i = 1;i <= n;i++)
64         {
65             scanf("%d",&b[i]);
66             sum2[i] = sum2[i-1] + b[i]; 
67         }
68         memset(dp,-1,sizeof(dp));
69         printf("%d\n",solve(1,n,1,n));
70     }
71     return 0;
72 }