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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#197802#3857. Single-track railwayForever_Young#ML 0ms0kbC++231.5kb2023-10-02 20:01:342023-10-02 20:01:35

Judging History

你现在查看的是最新测评结果

  • [2023-10-02 20:01:35]
  • 评测
  • 测评结果:ML
  • 用时:0ms
  • 内存:0kb
  • [2023-10-02 20:01:34]
  • 提交

answer

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=1;i<=n;++i)
#define per(i,n) for(int i=n;i>=1;--i)
#define pb push_back
#define mp make_pair
#define N 210000
#define inf 1000000000
int n;
int a[N];
int st[4*N];
void build(int t,int l,int r)
{
	if (l==r){ st[t]=a[l]; return; }
	int mid=(l+r)/2;
	build(2*t,l,mid);
	build(2*t+1,mid+1,r);
	st[t]=st[2*t]+st[2*t+1];
}
void modify(int t,int l,int r,int k,int p)
{
	if (l==r){ st[t]=p; return; }
	int mid=(l+r)/2;
	if (k<=mid)modify(2*t,l,mid,k,p);
	else modify(2*t+1,mid+1,r,k,p);
	st[t]=st[2*t]+st[2*t+1];
}
long long getsum(int t,int l,int r,int a,int b)
{
	if (a<=l && r<=b)return st[t];
	int mid=(l+r)/2;
	long long ret=0;
	if (a<=mid)ret+=getsum(2*t,l,mid,a,b);
	if (b>mid)ret+=getsum(2*t+1,mid+1,r,a,b);
	return ret;
}
long long getans()
{
	int l=1,r=n;
	while (l<r)
	{
		int mid=(l+r)/2;
		if (getsum(1,1,n-1,1,mid-1)*2>=st[1])r=mid;
		else l=mid+1;
	}
	long long ans=2147483647ll*100000ll,ansp;
	for(int i=max(1,l-2);i<=min(n,l+2);i++)
	{
		long long wait=abs(getsum(1,1,n-1,1,i-1)-getsum(1,1,n-1,i,n-1));
		if (wait<ans)ans=wait,ansp=i;
	}
	return ans;
}
int main()
{
	cin>>n;
	rep(i,n-1)scanf("%d",&a[i]);
	build(1,1,n-1);
	printf("%lld\n",getans());
	int q; cin>>q;
	while (q--)
	{
		int x,y; scanf("%d%d",&x,&y);
		modify(1,1,n-1,x,y);
		printf("%lld\n",getans());
	}
}

Details

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Test #1:

score: 0
Memory Limit Exceeded

input:

2
39
7
1 20
1 70
1 56
1 37
1 37
1 37
1 91

output:


result: