HNUOJ 13341

题目给你一个串， 串是严格的 1 – n 的排列，里面的数是随机的

把这个串里面的数字分别输出//先预处理，对于给出的串能找到里面的最大数，再 DFS 处理

#include<iostream>
#include<string>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<stack>
using namespace std;
bool Jug[100];
string num[55]; 
string str;
int len,Num;
stack<int> Sum;
bool Dfs(int n) {
    if(n >= len) {
        if(Jug[Num] == true) return true;
        return false;
    }
    int a,b;
    if(n <len) a = str[n] - '0';
    if(n < len-1) b = a*10 + str[n+1] - '0';
    if(a==0) return false;
    if(Jug[a] == false && n <len) {
        Jug[a] = true;
        if(Dfs(n+1)) 
        {
            Sum.push(a);
            return true;
        }
        Jug[a] = false;
    }
    if(b <= 50 && Jug[b] == false && n < len-1) {
        Jug[b] = true;
        if(Dfs(n+2)) {
            Sum.push(b);
            return true;
        }
        Jug[b] = false;
    }
    return false;
}
int main() {
    num[1] = "1";
    for(int i = 2; i <= 50; ++i) if(i < 10) num[i] = (num[i-1] + char(i + '0'));
    else num[i] = (num[i-1] + char(i/10 + '0') + char (i % 10 + '0'));
    for(int i = 1; i <= 50; ++i) sort(num[i].begin(),num[i].end());
    //////////////
    
    while(cin >> str) {
    Num = 0;
    memset(Jug,false,sizeof(Jug));
    while(!Sum.empty()) Sum.pop();
    string s = str;
    sort(s.begin(),s.end());
    for(int i = 1; i <= 50; ++i) if(s == num[i]) {
        Num = i; break;
    }
    //cout << Num << endl;
    len = str.length();
    Dfs(0);
    while(!Sum.empty()) {
        cout << Sum.top() << " ";
        Sum.pop();
    }
    cout << endl;
}
}