HDU 1258 DFS

要注意的就是 處理 相同的數字;

/* *HDU 1258 *fuqiang11 *DFS *2013/7/28*/#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cstdlib>#define maxn 13using namespace std;int T,N;int a[maxn];int visit[maxn];int flag;int cmp(int x, int y){    return x > y;}void DFS(int sum, int pos){    if(sum == T)    {        flag = 1;        int p = 0;        for(int i = 1; i <= N; i++)        {            if(visit[i]==1)            {                if(p)                    cout<<"+";                cout<<a[i];                p = 1;            }        }        cout<<endl;        return ;    }    for(int i = pos; i <= N; i++)    {        if(visit[i]==0 && sum + a[i] <= T)        {            visit[i] = 1;            DFS(sum+a[i],i+1);            visit[i] = 0;        }        while(i<=N && a[i]==a[i+1])            i++;    }}int main(){#ifndef ONLINE_JUDGE    freopen("in","r",stdin);#endif    while(cin>>T && T)    {        cin>>N;        memset(visit, 0, sizeof(visit));        for (int i = 1; i <= N; i++)        {            cin>>a[i];            if(a[i] > T)                visit[i] = -1;        }        cout<<"Sums of "<<T<<":"<<endl;        flag = 0;        sort(a+1,a+N+1,cmp);        DFS(0,1);        if(!flag)            cout<<"NONE"<<endl;    }}