CF1073D Berland Fair 二分+线段树

考场上切的，挺简单的~

Code:

#include <cstdio>
#include <algorithm>
#define N 200005
#define inf 1000000004
#define ll long long
#define setIO(s) freopen(s".in","r",stdin) , freopen(s".out","w",stdout)
using namespace std;
ll arr[N];
struct Seg
{
	#define lson (now<<1)
	#define rson (now<<1|1)
	struct Node
	{
		ll sum,minv;
	}t[N<<2];
	void pushup(int l,int r,int now)
	{
		t[now].sum=0;
		int mid=(l+r)>>1;
		if(mid>=l) t[now].sum+=t[lson].sum, t[now].minv=t[lson].minv;
		if(r>mid)  t[now].sum+=t[rson].sum, t[now].minv=min(t[now].minv, t[rson].minv);
	}
	void build(int l,int r,int now)
	{
		if(l==r)
		{
			t[now].sum=t[now].minv=arr[l];
			return;
		}
		int mid=(l+r)>>1;
		if(mid>=l) build(l,mid,lson);
		if(r>mid)  build(mid+1,r,rson);
		pushup(l,r,now);
	}
	void update(int l,int r,int now,int p,ll v)
	{
		if(l==r)
		{
			t[now].sum=v;
			t[now].minv=inf;
			return;
		}
		int mid=(l+r)>>1;
		if(p<=mid) update(l,mid,lson,p,v);
		else update(mid+1,r,rson,p,v);
		pushup(l,r,now);
	}
	ll query(int l,int r,int now,int L,int R)
	{
		if(l>=L&&r<=R) return t[now].sum;
		int mid=(l+r)>>1;
		ll re=0;
		if(L<=mid) re+=query(l,mid,lson,L,R);
		if(R>mid)  re+=query(mid+1,r,rson,L,R);
		return re;
	}
	#undef lson
	#undef rson
}seg;
int main()
{
	// setIO("fairs");
	int i,j,n,cnt;
	ll k,tot=0;
	scanf("%d%lld",&n,&k);
	for(i=1;i<=n;++i) scanf("%lld",&arr[i]);
	cnt=n;
	seg.build(1,n,1);
	while(1)
	{
		int l=1,r=n,mid,ans=0;
		while(l<=r)
		{
			mid=(l+r)>>1;
			if(seg.query(1,n,1,1,mid)<=k)
			{
				ans=mid,l=mid+1;
			}
			else r=mid-1;
		}
		if(ans==n)
		{
			tot+=(k/seg.t[1].sum)*cnt;
			k-=(k/seg.t[1].sum)*seg.t[1].sum;
		}
		else if(seg.t[1].minv>k) break;
		else
		{
			--cnt;
			seg.update(1,n,1,ans+1,0);
		}
	}
	printf("%lld\n",tot);
	return 0;
}