Numbers

直接dfs即可...emmm好水,好了,学树状数组线段树去了...ggg

#include <bits/stdc++.h>
using namespace std;
const int N=100;
string s;
int vis[N],ans;

void dfs(int u,int op)
{
    //cout<<s.size()<<endl;
    //cout<<u<<' '<<op<<endl;
    if(op==1)
    {
        if(vis[s[u]-'0']) return;
        vis[s[u]-'0']=1;
        if(u==s.size()-1)
        {
            ans++;
            vis[s[u]-'0']=0;
            return;
        }
        dfs(u+1,1);
        dfs(u+1,2);
        vis[s[u]-'0']=0;
    }
    else
    {
        if(u+1>=s.size()) return;
        if(vis[(s[u]-'0')*10+(s[u+1]-'0')]||(s[u]-'0')==0) return;
        vis[(s[u]-'0')*10+(s[u+1]-'0')]=1;
        if(u==s.size()-2)
        {
            ans++;
            vis[(s[u]-'0')*10+(s[u+1]-'0')]=0;
            return;
        }
        dfs(u+2,1);
        dfs(u+2,2);
        vis[(s[u]-'0')*10+(s[u+1]-'0')]=0;
    }
}

int main()
{
    while(cin>>s)
    {
        ans=0;
        memset(vis,0,sizeof vis);
        dfs(0,1);
        dfs(0,2);
        printf("%d\n",ans);
    }
    return 0;
}