rt，Segment Tree Beats 复杂度假了，不知道为什么，悬赏两个关注。

#include <bits/stdc++.h>
#define lc(x) ((x)<<1)
#define rc(x) (((x)<<1)|1)
using namespace std;
struct rope
{
	long long l,r;
}a[200000];
struct ask
{
	long long l,r,p;
}b[200000]; 
struct node
{
	long long mx,se;
}tr[800000];
long long n,m,q,ans[200000],rt=1;
bool cmp1(struct rope a,struct rope b)
{
	return a.r<b.r;
}

bool cmp2(struct ask a,struct ask b)
{
	return a.r<b.r;
}

void pushup(long long x)
{
	tr[x].mx=max(tr[lc(x)].mx,tr[rc(x)].mx);
	if(tr[x].mx==tr[lc(x)].mx)tr[x].se=max(tr[lc(x)].se,tr[rc(x)].mx);
	else if(tr[x].mx==tr[rc(x)].mx)tr[x].se=max(tr[lc(x)].mx,tr[rc(x)].se);
	else tr[x].se=max(tr[lc(x)].se,tr[rc(x)].se);
}

void pushdown(long long x)
{
	long long pl=tr[lc(x)].mx,pr=tr[rc(x)].mx;
	if(pl>=pr)tr[lc(x)].mx=tr[x].mx;
	if(pl<=pr)tr[rc(x)].mx=tr[x].mx;
}

void build(long long x,long long l,long long r)
{
	tr[x].mx=tr[x].se=-1e18;
	if(l==r)
	   {
	   tr[x].mx=l;
	   return;
       }
	long long mid=(l+r)>>1;
	build(lc(x),l,mid),build(rc(x),mid+1,r);
	pushup(x);
}

void modify(long long x,long long l,long long r,long long lx,long long rx,long long k,long long w)
{
	if(tr[x].mx<k)return;
	if(l>=lx&&r<=rx&&tr[x].se<k&&tr[x].mx>=k)
	   {
	   	tr[x].mx=w;
	   	return;
	   }
	pushdown(x);
	long long mid=(l+r)>>1;
	if(lx<=mid)modify(lc(x),l,mid,lx,rx,k,w);
	if(rx>=mid+1)modify(rc(x),mid+1,r,lx,rx,k,w);
	pushup(x);
}

long long query(long long x,long long l,long long r,long long p)
{
	if(l==r)return tr[x].mx;
	pushdown(x);
	long long mid=(l+r)>>1;
	if(p<=mid)return query(lc(x),l,mid,p);
	else return query(rc(x),mid+1,r,p);
}

int main()
{
	scanf("%lld%lld",&n,&m);
	for(int i=1;i<=m;i++)scanf("%lld%lld",&a[i].l,&a[i].r);
	scanf("%lld",&q);
	for(int i=1;i<=q;i++)scanf("%lld%lld",&b[i].l,&b[i].r),b[i].p=i;
	sort(a+1,a+m+1,cmp1),sort(b+1,b+q+1,cmp2);
	build(rt,1,n);
	long long r1=1,r2=1;
	for(int i=1;i<=n;i++)
	    {
	    	while(a[r1].r<=i&&r1<=m)modify(rt,1,n,1,a[r1].l,a[r1].l,a[r1].r),r1++;
	    	while(b[r2].r<=i&&r2<=q)ans[b[r2].p]=query(rt,1,n,b[r2].l),r2++;
		}
	for(int i=1;i<=q;i++)printf("%lld\n",ans[i]);
	return 0;
}