codeforces189A - Cut Ribbon DP

 1 // File Name: 189a.cpp
 2 // Author: darkdream
 3 // Created Time: 2014年07月24日 星期四 08时11分26秒
 4 
 5 #include<vector>
 6 #include<list>
 7 #include<map>
 8 #include<set>
 9 #include<deque>
10 #include<stack>
11 #include<bitset>
12 #include<algorithm>
13 #include<functional>
14 #include<numeric>
15 #include<utility>
16 #include<sstream>
17 #include<iostream>
18 #include<iomanip>
19 #include<cstdio>
20 #include<cmath>
21 #include<cstdlib>
22 #include<cstring>
23 #include<ctime>
24 
25 using namespace std;
26 int ans[4][4005];
27 int main(){
28     int n , a[4] ;
29     memset(ans,0,sizeof(ans));
30     scanf("%d %d %d %d",&n,&a[1],&a[2],&a[3]);
31     ans[0][0] = 1; 
32     for(int i =1;i <= 3;i ++)
33     {
34        for(int j = 0;j<= 4000;j++)
35        {
36           if(j < a[i] || ans[i][j-a[i]] == 0)
37               ans[i][j] = ans[i-1][j];
38           else {
39               ans[i][j] = max(ans[i][j-a[i]]+1,ans[i-1][j]);
40           }
41        }
42 
43     }
44 /*    for(int i =1;i <= 3; i ++)
45     {
46          for(int j =1;j <= 7;j ++)
47              printf("%d ",ans[i][j]);
48          printf("\n");
49     }*/
50     printf("%d\n",ans[3][n]-1);
51     
52     
53     return 0;
54 }