SPOJ GSS2 Can you answer these queries II ——线段树

#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>

#include <map>
#include <set>
#include <queue>
#include <string>
#include <iostream>
#include <algorithm>

using namespace std;

#define maxn 1000005
#define inf 0x3f3f3f3f
#define F(i,j,k) for (int i=j;i<=k;++i)
#define D(i,j,k) for (int i=j;i>=k;--i)

void Finout()
{
    #ifndef ONLINE_JUDGE
    freopen("in.txt","r",stdin);
    freopen("wa.txt","w",stdout);
    #endif
}

int Getint()
{
    int x=0,f=1; char ch=getchar();
    while (ch<‘0‘||ch>‘9‘) {if (ch==‘-‘) f=-1; ch=getchar();}
    while (ch>=‘0‘&&ch<=‘9‘) {x=x*10+ch-‘0‘; ch=getchar();}
    return x*f;
}

const int buf=200005;
int n,m,a[maxn],last[maxn],bac[maxn];
struct Que{int l,r,id,ans;}q[maxn];

struct Segment_Tree{
	int L,R,C;
	int old_mx[maxn],old_lazy[maxn];
	int now_mx[maxn],now_lazy[maxn];
	void init()
	{
		memset(old_mx,0,sizeof old_mx);
		memset(now_mx,0,sizeof now_mx);
		memset(old_lazy,0,sizeof old_lazy);
		memset(now_lazy,0,sizeof now_lazy);
	}
	void update(int o,int l,int r)
	{
		old_mx[o]=max(old_mx[o<<1],old_mx[o<<1|1]);
		now_mx[o]=max(now_mx[o<<1],now_mx[o<<1|1]);
	}
	void pushdown(int o,int l,int r)
	{
		old_lazy[o<<1]=max(old_lazy[o<<1],now_lazy[o<<1]+old_lazy[o]);
		old_lazy[o<<1|1]=max(old_lazy[o<<1|1],now_lazy[o<<1|1]+old_lazy[o]);
		
		old_mx[o<<1]=max(old_mx[o<<1],now_mx[o<<1]+old_lazy[o]);
		old_mx[o<<1|1]=max(old_mx[o<<1|1],now_mx[o<<1|1]+old_lazy[o]);
		
		now_lazy[o<<1]+=now_lazy[o];
		now_lazy[o<<1|1]+=now_lazy[o];
		
		now_mx[o<<1]+=now_lazy[o];
		now_mx[o<<1|1]+=now_lazy[o];
		
		now_lazy[o]=old_lazy[o]=0;
	}
	void add(int o,int l,int r)
	{
		if (L<=l&&r<=R)
		{
			old_lazy[o]=max(old_lazy[o],now_lazy[o]+=C);
			old_mx[o]=max(old_mx[o],now_mx[o]+=C);
			return ;
		}
		pushdown(o,l,r);
		int mid=l+r>>1;
		if (R<=mid) add(o<<1,l,mid);
		else if (L>mid) add(o<<1|1,mid+1,r);
		else add(o<<1,l,mid),add(o<<1|1,mid+1,r);
		update(o,l,r);
	}
	int query(int o,int l,int r)
	{
		if (L<=l&&r<=R) return old_mx[o];
		pushdown(o,l,r);
		int mid=l+r>>1;
		if (R<=mid) return query(o<<1,l,mid);
		if (L>mid) return query(o<<1|1,mid+1,r);
		else return max(query(o<<1,l,mid),query(o<<1|1,mid+1,r));
	}
}t;

bool cmp1(Que x,Que y){return x.r<y.r;}
bool cmp2(Que x,Que y){return x.id<y.id;}

int main()
{
    Finout();
	n=Getint();
	F(i,1,n) a[i]=Getint();
	F(i,1,n)
	{
		last[i]=bac[a[i]+buf];
		bac[a[i]+buf]=i;
	}
	m=Getint();
	F(i,1,m)
	{
		q[i].l=Getint();
		q[i].r=Getint();
		q[i].id=i; 
	}
	sort(q+1,q+m+1,cmp1);
	int h=0;
	F(i,1,m)
	{
		while (h<q[i].r&&h<=n)
		{
			h++;
			t.L=last[h]+1;
			t.R=h;
			t.C=a[h];
//			printf("Add %d %d %d\n",t.L,t.R,t.C);
			t.add(1,1,n);
		}
		t.L=q[i].l;t.R=q[i].r;
//		printf("Query %d %d for %d\n",q[i].l,q[i].r,q[i].id);
		q[i].ans=t.query(1,1,n);
	}
	sort(q+1,q+m+1,cmp2);
	F(i,1,m) printf("%d\n",q[i].ans);
}