CF922 div2 D. Blocking Elements

题面

代码

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#include<bits/stdc++.h>
using namespace std;
#define IOS ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,a,n) for(int i=n;i>=a;i--)
#define endl "\n"
#define fi first
#define se second 
#define pb push_back
#define mid (l+r)/2
#define ls i<<1
#define rs i<<1|1
using ll=long long;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
#define N 100100
ll dp[N],s[N],t[N<<2];
int a[N],n;
ll sum(int l,int r){
	if(l>r) return 0;
	return s[r]-s[l-1];
}
int find(int ri,ll x){
	int l=0,r=ri-1;
	int ans=-1;
	while(l<=r){
		//cout<<l<<" "<<r<<endl;
		//return -1;
		if(sum(mid+1,ri-1)<=x) ans=mid,r=mid-1;
		else l=mid+1;
	}
	return ans;
}
void pu(int i){
	t[i]=min(t[ls],t[rs]);
}
void cha(int i,int l,int r,int pos,ll k){
	if(l==r&&r==pos){
		t[i]=k;return;
	}
	if(pos<=mid) cha(ls,l,mid,pos,k);
	else cha(rs,mid+1,r,pos,k);
	pu(i);
}
ll que(int i,int l,int r,int cl,int cr){
	//cout<<l<<" "<<r<<endl;
	if(l>=cl&&r<=cr) return t[i];
	if(l>cr||r<cl) return 1e15;
	return min(que(ls,l,mid,cl,cr),que(rs,mid+1,r,cl,cr));
}
bool check(ll x){
	cha(1,0,n+1,0,0);
	rep(i,1,n+1){
		int idx=find(i,x);
		//cout<<i<<" "<<x<<" "<<idx<<endl;
		dp[i]=a[i]+que(1,0,n+1,idx,i-1);
		//cout<<que(1,0,n+1,idx,i-1)<<" "<<dp[i]<<endl;
		cha(1,0,n+1,i,dp[i]);
	}
	if(dp[n+1]>x) return false;
	else return true;
}
void solve(){
	rep(i,1,n+1) a[i]=0;
	rep(i,1,4*n+100) t[i]=1e15;
	cin>>n;
	rep(i,1,n) cin>>a[i],s[i]=s[i-1]+a[i];
	ll l=1,r=1e14+10;
	ll ans=-1;
	while(l<=r){
		//cout<<l<<" "<<r<<endl;
		if(check(mid)) ans=mid,r=mid-1;
		else l=mid+1;
	}
	cout<<ans<<endl;
}
int main(){
	IOS
	int t=1;cin>>t;
	while(t--) solve();
	return 0;
}
/*
3
6
1 4 5 3 3 2
5
1 2 3 4 5
6
4 1 6 3 10 7

1
6
1 4 5 3 3 2
*/