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POJ 1011 / UVA 307 Sticks

中文题（一般都比较坑）

思路：DFS
这里写图片描述
（感谢学长的幻灯片）

这破题把我折腾惨了！！！搞了n天

// by Sirius_Ren
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int n,a[100],sum,jy,maxx,q;
bool vis[100];
bool cmp(int a,int b){return a>b;}
bool dfs(int x,int l,int pos){
    if(x==q)return 1;
    for(int i=pos+1;i<=n;i++){
        if(vis[i]||(!vis[i-1]&&a[i]==a[i-1]&&i>1))continue;
        if(l==a[i]){
            vis[i]=1;
            if(dfs(x+1,jy,0))return 1;
            vis[i]=0;return 0;
        }
        if(l>a[i]){
                vis[i]=1;
                if(dfs(x,l-a[i],i))return 1;
                vis[i]=0;
                if(l==jy)return 0;
            }
        }
    return 0;
}   
int main()
{
    while(scanf("%d",&n)&&n){
        maxx=sum=0;
        memset(a,0,sizeof(a));
        for(int i=1;i<=n;i++)scanf("%d",&a[i]),sum+=a[i],maxx=max(maxx,a[i]);
        sort(a+1,a+1+n,cmp);
        for(jy=maxx;jy<=sum;jy++){
            if(sum%jy)continue;
            q=sum/jy;
            memset(vis,0,sizeof(vis));
            if(dfs(0,jy,0)){printf("%d
",jy);break;}
        }
    }
}