Fridge

#include <iostream>
using namespace std;
char s[1000101];
int cnt[10];
int main(){
	cin>>s;
	int i=0;
	while(s[i])++cnt[s[i++]-'0'];
	for(int i=1;;++i){
		for(int j=1;j<10;++j){
			if(cnt[j]<i){
				for(int k=0;k<i;++k){
					cout<<(char)(j+'0');
				}
				cout<<'\n';
				return 0;
			}
		}
		if(cnt[0]<i){
			cout<<'1';
			for(int k=0;k<i;++k){
				cout<<'0';
			}
			cout<<'\n';
			return 0;
		}
	}
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED