Manthan, Codefest 18 (rated, Div. 1 + Div. 2)A B C

#include <iostream>
using namespace std;
int cnt;
void solve(int n)
{
	cnt=0;
	while(n>=(1<<(cnt)))
	{
		cnt++;
	}
}
int main()
{
	int n;
	cnt=0;
	scanf("%d",&n);	
	
	solve(n);
	printf("%d\n",cnt);
	
	return 0;
} 

#include <iostream>
#include <algorithm>
#define ll long long 
using namespace std;
ll a[400005];
int main()
{
	ll s;
	int n;
	
	scanf("%lld %lld",&n,&s);
	
	for(int i=0;i<n;i++)
	scanf("%lld",&a[i]);
	
	ll ans=0;
	int m=n/2;
	sort(a,a+n);
	if(a[m]==s);
	else if(a[m]<s)
	{
		int i=m;
		while(a[i]<s&&i<n)
		{
			ans+=s-a[i];
			i++;
		}
	}else 
	{
			int i=m;
		while(a[i]>s&&i>=0)
		{
			ans+=a[i]-s;
			i--;
		}
    }
	printf("%lld\n",ans);

	return 0;
} 

#include <iostream>
#include <algorithm>
#include <string>
#define ll long long 
using namespace std;
int main()
{
	char a[1000005],b[1000005];
	int n;
	scanf("%d",&n);
	getchar();
	scanf("%s",a);
	getchar();
	scanf("%s",b);
	int i=0,ans=0;
	while(i<n)
	{
		if(a[i]!=b[i])
		{
			if((i+1)<n&&a[i+1]==b[i]&&a[i]==b[i+1])
			{
				ans+=1; i++;
			}else ans++;
		}
		i++;
	}
	printf("%d\n",ans);
	return 0;
}