HDU-1258 Sum It Up

题意：给出sum和n个数，找出满足m（m<=n）个数相加等于sum。

思路：dfs.

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1258

View Code

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <cstdlib>
 4 #include <cmath>
 5 #include <string>
 6 #include <algorithm>
 7 #include <iostream>
 8 using namespace std;
 9 const int N=110;
10 
11 int a[N],b[N];
12 int n,sum;
13 bool vis[N],flag;
14 
15 void dfs(int s,int ssum,int cnt){
16     if(ssum==sum){
17         for(int i=1;i<=cnt;i++) printf(i==cnt?"%d\n":"%d+",b[i]);
18         flag=true;
19         return ;
20     }
21     int last=-1;
22     for(int i=s+1;i<=n;i++){
23         if(!vis[i]&&last!=a[i]){
24             last=a[i];
25             vis[i]=true;
26             b[cnt+1]=a[i];
27             dfs(i,ssum+a[i],cnt+1);
28             vis[i]=false;
29         }
30     }
31 }
32 
33 int main(){
34     
35 //    freopen("data.in","r",stdin);
36 //    freopen("data.out","w",stdout);
37     
38     while(scanf("%d%d",&sum,&n),sum||n){
39         printf("Sums of %d:\n",sum);
40         for(int i=1;i<=n;i++) scanf("%d",&a[i]);
41         memset(b,0,sizeof(b));
42         memset(vis,false,sizeof(vis));
43         flag=false;
44         dfs(0,0,0);
45         if(!flag) puts("NONE");
46     }
47     return 0;
48 }

posted @ 2012-06-18 08:58 Hug_Sea 阅读(161) 评论(0) 收藏举报

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