这个代码wa了2个，怎么也找不到错，大佬帮忙看看背

// Problem: P1678 烦恼的高考志愿
// Contest: Luogu
// URL: https://www.luogu.com.cn/problem/P1678
// Memory Limit: 125 MB
// Time Limit: 1000 ms



#include <bits/stdc++.h>
using namespace std;
//#define MAXN 100010
#define rep(i,a,n) for (ll i=a;i<=n;++i)
#define per(i,a,n) for (ll i=n;i>=a;--i)
#define INF 1000000000
#define F first
#define S second
#define pb push_back
#define mp make_pair
#define pob pop_back
#define all(x) (x).begin(),(x).end()
#define ent cout<<'\n'
const int N = 100010;
typedef vector<int> vi;
typedef long long ll;
typedef pair<int, int> pii;
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
ll n, m;
ll s[N],a[N];

int main()
{
	ios::sync_with_stdio(0); cin.tie(0), cout.tie(0);
	
	cin>>m>>n;
	for(int i=0;i<m;++i) cin>>s[i];
	for(int i=0;i<n;++i)cin>>a[i];
	
	ll res=0;
	
	sort(s,s+m);
	sort(a,a+n);
	for(int i=0;i<n;++i)
	{
		if(a[i]<s[0]) 
		{
			res+=s[0]-a[i];
			continue;
		}
		else if(a[i]>s[m-1]) 
		{
			res+=s[m-1]-a[i];
			continue;
		}
		ll p1=lower_bound(s,s+m,a[i])-s;
		if(s[p1]!=a[i])
		{
			ll p2=p1-1;
			if( (s[p1]-a[i]) > (a[i]-s[p2]) )
				res += a[i]-s[p2];
			else
				res+=s[p1]-a[i];
			
		}
	}
	
	cout<<res;

	return 0;
}