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Description
You have a long drive by car ahead. You have a tape recorder, but unfortunately your best music is on CDs. You need to have it on tapes so the problem to solve is: you have a tape N minutes long. How to choose tracks from CD to get most out of tape space and have as short unused space as possible.
Assumptions:
Program should find the set of tracks which fills the tape best and print it in the same sequence as the tracks are stored on the CD
5 3 1 3 4 10 4 9 8 4 2 20 4 10 5 7 4 90 8 10 23 1 2 3 4 5 7 45 8 4 10 44 43 12 9 8 2
1 4 sum:5 8 2 sum:10 10 5 4 sum:19 10 23 1 2 3 4 5 7 sum:55 4 10 12 9 8 2 sum:45
题意：给出数m和n，再给出n个数，求从n个数中选出几个和最大的数，并按循序输出这些书和这些数的和。
dfs搜索并记录路径就可以了。也可以用01背包。
dfs:
1 #include<cstdio> 2 #include<cstring> 3 #include<algorithm> 4 using namespace std; 5 int n,m,n1,sum,ans[22],a[22],str[22]; 6 void dfs(int x,int s,int p) 7 { 8 if (s>m) return ; 9 if (s>sum) 10 { 11 sum=s; 12 for (int i=0;i<p;i++) ans[i]=str[i]; 13 n1=p; 14 } 15 for (int i=x+1;i<=n;i++) 16 { 17 str[p]=a[i]; 18 dfs(i,s+a[i],p+1); 19 } 20 } 21 int main() 22 { 23 int i; 24 while (~scanf("%d%d",&m,&n)) 25 { 26 sum=0; 27 n1=0; 28 for (i=1;i<=n;i++) scanf("%d",&a[i]); 29 dfs(0,0,0); 30 for (i=0;i<n1;i++) printf("%d ",ans[i]); 31 printf("sum:%d\n",sum); 32 } 33 return 0; 34 }
01:
1 #include<cstdio> 2 #include<cstring> 3 #include<algorithm> 4 using namespace std; 5 int dp[10005],v[22][10005]; 6 int main() 7 { 8 int n,m,i,j; 9 int a[22]; 10 while (~scanf("%d%d",&m,&n)) 11 { 12 memset(dp,0,sizeof(dp)); 13 memset(v,0,sizeof(v)); 14 for (i=1;i<=n;i++) scanf("%d",&a[i]); 15 for (i=n;i>=1;i--) 16 { 17 for (j=m;j>=a[i];j--) 18 { 19 if (dp[j]<dp[j-a[i]]+a[i]) 20 { 21 dp[j]=dp[j-a[i]]+a[i]; 22 v[i][j]=1; 23 } 24 } 25 } 26 for (i=1,j=dp[m];i<=n;i++) 27 { 28 if (v[i][j]) 29 { 30 printf("%d ",a[i]); 31 j-=a[i]; 32 } 33 } 34 printf("sum:%d\n",dp[m]); 35 } 36 return 0; 37 }
UVA 624 CD (01背包+打印路径 或 dfs+记录路径）
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原文地址：http://www.cnblogs.com/pblr/p/4868972.html
