tyvj1271 零式求和

#include<iostream>
using namespace std;
int n,ans[20],acc;
void judge(){
    int sign = 1;
    int now = 0;
    int next = 1;
    for(int i = 1;i < n;i++){
        if(ans[i] == 3){
            next = next * 10 + (i+1);
        }else{
            if(sign == 1) now += next;
            if(sign == 2) now -= next;
            if(ans[i] == 1) sign = 1;
            if(ans[i] == 2) sign = 2;
            next = i + 1;
        }
    }
    if(sign == 1) now += next;
    if(sign == 2) now -= next;
    if(!now){
        for(int i = 1;i < n;i++){
            cout<<i;
            if(ans[i] == 1) cout<<"+";
            if(ans[i] == 2) cout<<"-";
            if(ans[i] == 3) cout<<" ";
        }
        cout<<n<<endl;
    }
}
int dfs(int deep){
    if(deep == n){
        judge();
        return 0;
    }
    ans[deep] = 3;
    dfs(deep+1);
    ans[deep] = 1;
    dfs(deep+1);
    ans[deep] = 2;
    dfs(deep+1);
}
int main(){
    cin>>n;
    dfs(1);
    return 0;
}