题意:
木棒复原,输入n,再输入n个木棒长度,求原来木棒长度最小为多少
解题思路:
dfs+回溯
具体代码:
#include<iostream> #include<algorithm> using namespace std; int n; int cmp(int a,int b) { if(a>b) return 1; else return 0; } int dfs(int *stick,bool *vist,int len,int initlen,int s,int num) { if(num==n) return true; int sample=-1; for(int i=s;i<n;i++) { if(vist[i]||stick[i]==sample) continue; vist[i]=true; if(len+stick[i]<initlen) { if(dfs(stick,vist,len+stick[i],initlen,i,num+1)) return true; else sample=stick[i]; } else if(len+stick[i]==initlen) { if(dfs(stick,vist,0,initlen,0,num+1)) return true; else sample=stick[i]; } vist[i]=false; if(len==0) break; } return false; } int main() { while(cin>>n && n) { int *stick=new int[n]; bool *vist=new bool[n]; int sumlen=0; for(int i=0;i<n;i++) { cin>>stick[i]; sumlen+=stick[i]; vist[i]=false; } sort(stick,stick+n,cmp); int maxlen=stick[0];//所有木棒中最长的 bool flag=false; for(int initlen=maxlen;initlen<=sumlen-initlen;initlen++) { if(!(sumlen%initlen)&&dfs(stick,vist,0,initlen,0,0)) { cout<<initlen<<endl; flag=true; break; } } if(!flag) cout<<sumlen<<endl; delete stick; delete vist; } return 0; }