位置 fort until cst == memset miss 分鐘 rac

It is a little known fact that cows love apples. Farmer John has two apple trees (which are conveniently numbered 1 and 2) in his field, each full of apples. Bessie cannot reach the apples when they are on the tree, so she must wait for them to fall. However, she must catch them in the air since the apples bruise when they hit the ground (and no one wants to eat bruised apples). Bessie is a quick eater, so an apple she does catch is eaten in just a few seconds.

Each minute, one of the two apple trees drops an apple. Bessie, having much practice, can catch an apple if she is standing under a tree from which one falls. While Bessie can walk between the two trees quickly (in much less than a minute), she can stand under only one tree at any time. Moreover, cows do not get a lot of exercise, so she is not willing to walk back and forth between the trees endlessly (and thus misses some apples).

Apples fall (one each minute) for T (1 <= T <= 1,000) minutes. Bessie is willing to walk back and forth at most W (1 <= W <= 30) times. Given which tree will drop an apple each minute, determine the maximum number of apples which Bessie can catch. Bessie starts at tree 1.Input

* Line 1: Two space separated integers: T and W

* Lines 2..T+1: 1 or 2: the tree that will drop an apple each minute.

Output

* Line 1: The maximum number of apples Bessie can catch without walking more than W times.

Sample Input

7 2
2
1
1
2
2
1
1

Sample Output

6

Hint

INPUT DETAILS:

Seven apples fall - one from tree 2, then two in a row from tree 1, then two in a row from tree 2, then two in a row from tree 1. Bessie is willing to walk from one tree to the other twice.

OUTPUT DETAILS:

Bessie can catch six apples by staying under tree 1 until the first two have dropped, then moving to tree 2 for the next two, then returning back to tree 1 for the final two. 題意：有兩棵樹1，2，每分鐘其中一棵樹會掉一顆蘋果，問T分鐘後最多能得到多少蘋果。註意：起始位置在1，左右移動最多K次，在一棵樹前能呆任意長時間。 題解：明顯的狀態表示，dp[ i ][ j ][ k ]表示 i 分鐘在 j 位置，用了 k 次移動所得到的最大值。其實第二維可以不開，因為起始位置在1，所以移動了k次後，當前位置 是k%2+1。

 1
 
 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 
 7 int T,K;
 8 int mp[1005],dp[1005][40];
 9 
10 void solve()
11 {   int ans=0;
12     for(int i=1;i<=T;i++){
13         for(int j=0;j<=K;j++){
14             if(j==0) dp[i][j]=dp[i-1][j];
15             else dp[i][j]=max(dp[i-1][j],dp[i-1][j-1]);
16             if(j%2+1==mp[i]) dp[i][j]+=1;
17             ans=max(ans,dp[i][j]);
18         }
19     }
20     cout<<ans<<endl; 
21 }
22 
23 int main()
24 {   cin>>T>>K;
25     for(int i=1;i<=T;i++) scanf("%d",&mp[i]);
26     memset(dp,0,sizeof(dp));
27     
28     solve();
29 }

Apple Catching POJ - 2385