https://www.luogu.com.cn/record/91253780

#include<bits/stdc++.h>
#define ll long long
using namespace std;
int n;
ll a[1000001], imp[1000001], scr[1000001], maxn=LONG_LONG_MIN, p;
bool Mod=false;
int main()
{
	cin>>n>>p;
	for(int i=1; i<=n; i++)
		cin>>a[i], imp[i]=max(imp[i-1], 0ll)+a[i];
	scr[1]=imp[1];
	maxn=2*imp[1];
	for(int i=2; i<=n; i++)
	{
		if(Mod)
			scr[i]=scr[i-1]+imp[i-1], scr[i]%=p;
		else
			scr[i]=maxn, maxn=max(maxn, scr[i]+imp[i]);
		//cout<<scr[i]<<endl;
		if(!Mod && scr[i]>scr[1])
			Mod=true;
	}
	ll fin=(Mod?scr[n]:scr[1]);
	cout<<(fin<0?"-":"")<<abs(fin)%p;
	return 0;
}

10分代码，求调