#include <cstdio>
using namespace std;
 
void recur_start(int len, int n);
void recur_process(char *buffer, int len, int start, int n);
 
int main() {
	recur_start(7, 3);
 
	return 0;
}
 
void recur_start(int len, int n) {
	char *buffer = new char[len + 1]; buffer[len] = 0;
 
	recur_process(buffer, len, 0, n);
 
	delete[] buffer;
}
 
void recur_process(char *buffer, int len, int start, int n) {
	if(start == len) {
		if(!n)
			puts(buffer);
		return;
	}
 
	if(n) {
		buffer[start] = '1';
		recur_process(buffer, len, start + 1, n - 1);
	}
 
	buffer[start] = '0';
	recur_process(buffer, len, start + 1, n);
}

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