poj 2205 Self

#include <iostream>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <math.h>#include <vector>#include <algorithm>using namespace std;struct Node{    char self[2005];};Node p[1000];int a[2005];int m;int b,n;char Change(int x){    if (x<=9)        return '0'+x;    else        return 'A'+x-10;}//从低位往高位搜索void dfs(int dep,int sum){    if(dep>n)    {        if(a[n]>0 || n == 1)        { for(int i=n; i>=1; i--) {     p[m].self[n-i] = Change(a[i]); } p[m].self[n] = ''; m++;        }        return;    }    int tol = 0;    for(a[dep]=0; a[dep]<b; a[dep]++)    {        tol = 0;        for(int i=1; i<=dep; i++)        { int j = dep-i+1; tol += a[i]*a[j];        }        if((tol+sum)%b == a[dep])        { dfs(dep+1,(tol+sum)/b);        }    }}bool cmp(Node a,Node b){    return strcmp(a.self,b.self)<0;}int main(){    while(scanf(" %d %d",&b,&n)!=EOF)    {        m = 0;        dfs(1,0);        sort(p,p+m,cmp);        printf("%dn",m);        for(int i=0; i<m; i++)        { printf("%sn",p[i].self);        }    }    return 0;}