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#include <stdio.h>
const int maxn=9;
int n;
char ans[2*maxn];
bool flag[maxn];
int rest;
int interrupt;
void dfs(int nowpos){
    if(!rest){
        ans[nowpos]='\0';//手动结尾,很重要 
        puts(ans);
        return;
    }
    if(nowpos&&ans[nowpos-1]!='-'){//不是第一个空并且前面不是'-' 
        ans[nowpos]='-';
        //修改标志 
        int temp=interrupt;
        interrupt=0;
        
        dfs(nowpos+1);
        //回溯标志 
        interrupt=temp;
    }
    for(int i=interrupt+1;i<=n;i++){
        if(flag[i]){
            ans[nowpos]='0'+i;
            
            //修改标志 
            flag[i]=false;
            rest-=1;
            int temp=interrupt;
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