Monistus

#include <bits/stdc++.h>

int num(int c){
	return (48>c || 57<c)?0:(int) c - 48;
}

#define st s.top()

int main(){
	FILE * f = stdin;
	char c = getc(f);
	int d, b[9], i;
	std::stack<std::queue<char>> s;
	while(c != 10){
		if(num((int)c)){
			i=0;
			d = num((int)c);
			while(i<d){
				if(!s.empty()){
					c = st.front();
					st.pop();
					if(st.empty()) s.pop();
				}else c = getc(f);
				b[i++] = c;
			}	
			std::queue<char> q;
			s.push(q);
			i=0;while(i<d) st.push(b[i++]);
			i=0;while(i<d) st.push(b[i++]);
		}else printf("%c", c);
		if(!s.empty()){
			c = st.front();
			st.pop();
			if(st.empty()) s.pop();
		}else c = getc(f);
	}
	printf("\n");
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 1, 2

Verdict: ACCEPTED

Test 7

Group: 1, 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: ACCEPTED

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: ACCEPTED

Test 14

Group: 2

Verdict: ACCEPTED