程序填空题：Sum of N-Narcissistic Number

An $n$-digit number that is the sum of the $n$-th powers of its digits is called an $n$-narcissistic number. For example, $153$ is a $3$-narcissistic number since $153=1^3+5^3+3^3$, and $1634$ is a $4$-narcissistic number since $1634=1^4+6^4+3^4+4^4$.

Please complete the following program that prints the sum of all $n$-narcissistic numbers.


```c++
#include 
long long cost[10], ans;
int cnt[10], t[10], n;
void dfs(int rest, int now, long long current) {
    if (rest == 0) {
        long long temp = current;
        for (int i = 0; i < 10; i++)
            t[i] = 0;
        while (temp > 0) {
            ++t[temp % 10];
            temp /= 10;
        }
        bool flag = 1;
        for (int i = 0; i < 10; i++)
            if (cnt[i] != t[i]) {
                flag = 0;
                break;
            }
        if (flag) {
            ;
        }
        return;
    }
    if () {
        return;
    }
    for (cnt[now] = 0; cnt[now] <= rest; cnt[now]++)
        dfs(rest - cnt[now], now + 1, );
     = 0;
}
int main()
{
    scanf("%d", &n);
    for (int i = 0; i < 10; i++) {
        cost[i] = 1;
        for (int j = 0; j < n; j++)
            cost[i] *= i;
    }
    dfs();
    printf("%lld\n",ans);
    return 0;
}
```






答案：
第1空：ans += current    

第2空：now > 9    

第3空：current + cost[now] * cnt[now]    

第4空：cnt[now]    

第5空：n, 0, 0