hdu 3496 Watch The Movie(二维费用背包)

二维费用背包问题

有两个限制条件：电影时长和看电影的部数。需要注意一下初始化dp[i][0] = 0,其余未知，因为看电影是一部一部来，所以当前dp值只能衔接前一部的dp值。

View Code

 1 /*

 2 Author:Zhaofa Fang

 3 Lang:C++

 4 */

 5 #include <cstdio>

 6 #include <cstdlib>

 7 #include <sstream>

 8 #include <iostream>

 9 #include <cmath>

10 #include <cstring>

11 #include <algorithm>

12 #include <string>

13 #include <utility>

14 #include <vector>

15 #include <queue>

16 #include <stack>

17 #include <map>

18 #include <set>

19 using namespace std;

20 

21 typedef long long ll;

22 #define DEBUG(x) cout<< #x << ':' << x << endl

23 #define REP(i,n) for(int i=0;i < (n);i++)

24 #define FOR(i,s,t) for(int i = (s);i <= (t);i++)

25 #define FORD(i,s,t) for(int i = (s);i >= (t);i--)

26 #define PII pair<int,int>

27 #define PB push_back

28 #define MP make_pair

29 #define ft first

30 #define sd second

31 #define lowbit(x) (x&(-x))

32 #define INF (1<<30)

33 

34 int dp[1005][105],ti[105],v[105];

35 int main()

36 {

37     //freopen("in","r",stdin);

38     //freopen("out","w",stdout);

39     int T;

40     scanf("%d",&T);

41     while(T--)

42     {

43         int n,m,L;

44         scanf("%d%d%d",&n,&m,&L);

45         REP(i,n)scanf("%d%d",&ti[i],&v[i]);

46         memset(dp,-1,sizeof(dp));

47         REP(i,L+1)dp[i][0] = 0;

48         REP(i,n)

49         {

50             FORD(j,L,ti[i])

51             {

52                 FORD(k,m,1)

53                 {

54                     if(dp[j-ti[i]][k-1]!=-1)dp[j][k] = max(dp[j][k],dp[j-ti[i]][k-1]+v[i]);

55                 }

56             }

57         }

58         if(dp[L][m]!=-1)printf("%d\n",dp[L][m]);

59         else puts("0");

60     }

61     return 0;

62 }