Codeforces Round #558 (Div. 2)

A

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

int main()
{
	int n,m;
	int c;
	
	scanf("%d %d",&n,&m);
	if(m==0){
		printf("1");
	}else{
		c=n-m;
		printf("%d",min(c,m));
	}
	
	
	return 0;
 } 

B

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

int main()
{
	vector<int> v,rv;
	
	for(int j=1;j<=10;j++){
		if(cnt[j]) v.push_back(cnt[j]);
	}
	sort(v.begin(),v.end());
	
	rv=v;
	if(v[0]==1){
		v.erase(v.begin());
		v.erase(unique(v.begin(),v.end())v.end());
		if(v.size()==1){
			ans=i;
		}
	}
	--rv[rv.size()-1];
	rv.erase(unique(rv.begin(),rv.end()),rv.end());
	if(rv.size()==1)
		ans=i;
	
	return 0;
}