K - Three swimmers

#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
    
    
    int t;
	long long a,b,c,p,x1,x2,x3;
	cin>>t; 
    while(t--)
    {
    
    
    	cin>>p>>a>>b>>c;
    	if(p%a==0||p%b==0||p%c==0)
    	{
    
    
    		cout<<"0"<<endl;
		}
		else
		{
    
    
			x1=a-p%a;//分别求出到岸边的最短时间
			x2=b-p%b;
			x3=c-p%c;
			
		  cout<<min(x1,min(x2,x3))<<endl;
		}
    	
	}
    return 0;
}

错误代码：

#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
    
    
    int t;
	long long a,b,c,p,x1,x2,x3;
	cin>>t; 
    while(t--)
    {
    
    
    	cin>>p>>a>>b>>c;
    	if(p==a||p==b||p==c)
    	{
    
    
    		cout<<"0"<<endl;
		}
		else
		{
    
    
			for(int i=1;;i++)
    	  {
    
    
    		if(p<=a)
    		{
    
    
    			x1=a-p;
    			break;
			}
    		else
    		a+=a;//这里的a值在不断变化，草率了~~~~~~~~
    		
		  }
		  for(int i=1;;i++)
		  {
    
    
		  	if(p<=b)
		  	{
    
    
		  		x2=b-p;
		  		break;
			}
			else
			b+=b;
		  }
		  for(int i=1;;i++)
		  {
    
    
		  	if(p<=c)
		  	{
    
    
		  		x3=c-p;
		  		break;
			}
			else
			c+=c;
		  }
		  cout<<min(x1,min(x2,x3))<<endl;
		}
    	
	}
    return 0;
}