USACO 3.4 Raucous Rockers

Raucous Rockers

You just inherited the rights to N (1 <= N <= 20) previously unreleased songs recorded by the popular group Raucous Rockers. You plan to release a set of M (1 <= M <= 20) compact disks with a selection of these songs. Each disk can hold a maximum of T (1 <= T <= 20) minutes of music, and a song can not overlap from one disk to another.

Since you are a classical music fan and have no way to judge the artistic merits of these songs, you decide on the following criteria for making the selection:

• The songs on the set of disks must appear in the order of the dates that they were written.
• The total number of songs included will be maximized.

PROGRAM NAME: rockers

INPUT FORMAT

Line 1:	Three integers: N, T, and M.
Line 2:	N integers that are the lengths of the songs ordered by the date they were written.

SAMPLE INPUT (file rockers.in)

4 5 2
4 3 4 2

OUTPUT FORMAT

A single line with an integer that is the number of songs that will fit on M disks.

SAMPLE OUTPUT (file rockers.out)

3
 
——————————————————————————
一道连我这种蒟蒻都能做出来的dp
dp(i,j)=dp(i-1,k)+packbag(v=t,k+1--j)
【i表示选了几个背包，j表示从前到后选了几首歌】
【然后做一个背包，关于容量为t然后从k+1到j之间选歌】
【背包预处理应该会更快，然而在线处理复杂度够了而且绰绰有余】

 /*
 ID: ivorysi
 PROG: rockers
 LANG: C++
 */
 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 #include <queue>
 #include <set>
 #include <vector>
 #include <string.h>
 #define siji(i,x,y) for(int i=(x);i<=(y);++i)
 #define gongzi(j,x,y) for(int j=(x);j>=(y);--j)
 #define xiaosiji(i,x,y) for(int i=(x);i<(y);++i)
 #define sigongzi(j,x,y) for(int j=(x);j>(y);--j)
 #define inf 0x3f3f3f3f
 #define MAXN 400005
 #define ivorysi
 #define mo 97797977
 #define ha 974711
 #define ba 47
 #define fi first
 #define se second
 #define pii pair<int,int>
 using namespace std;
 typedef long long ll;
 int n,m,t;
 int song[];
 int getso[][];
 int f[];
 inline int max(int a,int b){return a>b?a:b;}
 int check(int b,int e) {
     if(e<b) return ;
     memset(f,,sizeof(f));
     siji(i,b,e) {
         gongzi(j,t,song[i]) {
             f[j]=max(f[j],f[j-song[i]]+);
         }
     }
     return f[t];
 }
 void solve() {
     scanf("%d%d%d",&n,&t,&m);
     siji(i,,n) scanf("%d",&song[i]);
     siji(i,,m) {
         siji(j,,n) {
             xiaosiji(k,,j) {
                 getso[i][j]=max(getso[i][j],getso[i-][k]+check(k+,j));
             }
         }
     }
     printf("%d\n",getso[m][n]);
 }
 int main(int argc, char const *argv[])
 {
 #ifdef ivorysi
     freopen("rockers.in","r",stdin);
     freopen("rockers.out","w",stdout);
 #else
     freopen("f1.in","r",stdin);
 #endif
     solve();
 }