入门赛 E 题。

#include<bits/stdc++.h>
using namespace std;

#define int long long
#define double register int
#define ri register int

const int N = 1e5 + 5;

int n, a[N];

inline int change(int x){
	for(int i = 1; i <= a[x]; i++){
		int sum = 0;
		while(x){
			sum += x % 10;
			x /= 10;
		}
		x = sum;
		if(x <= 9) break;
	}
	return x;
}

signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	
	cin >> n;
	
	for(int i = 1; i <= n; i++) cin >> a[i];
	
	for(int i = 1; i <= n; i++) cout << change(i) << ' ';	
	
	return 0;
}

就 WA 了。

#include<bits/stdc++.h>
using namespace std;

#define int long long
#define double register int
#define ri register int

const int N = 1e5 + 5;

int n, a[N];

signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	
	cin >> n;
	
	for(int i = 1; i <= n; i++) cin >> a[i];
	
	for(int i = 1; i <= n; i++){
		int x = i;
		for(int j = 1; j <= a[i]; j++){
			int sum = 0;
			while(x){
				sum += x % 10;
				x /= 10;
			}
			x = sum;
			if(x <= 9) break;
		}
		cout << x << ' ';
	}
	
	return 0;
}

就对了。