Mayor's posters POJ 2528
传送门
线段树区间修改加离散化
#include <cstdio>
#include <iostream>
#include <queue>
#include <cmath>
#include <algorithm>
#include <cstring>
using namespace std;
#define ll long long
#define P pair<int,int>
const ll INF=1e18;
const int N=1e6+10;
int ans[N];
int l[N],r[N];
struct SegmentTree{
int l,r;
ll dat;
}t[N*4];
void build(int p,int l,int r)
{
t[p].l = l;
t[p].r = r;
t[p].dat = 0;
if(t[p].l == t[p].r){t[p].dat = 0;return ;}
int mid = (l+r)/2;
build(p*2,l,mid);
build(p*2+1,mid+1,r);
}
void spread(int p)
{
if(t[p].dat)
{
t[p*2].dat = t[p].dat;
t[p*2+1].dat = t[p].dat;
t[p].dat = 0;
}
}
void change(int p,int l,int r,ll v)
{
if(l <= t[p].l && t[p].r <= r)
{
t[p].dat = v;
return ;
}
int mid = (t[p].l+t[p].r)/2;
spread(p);
if(l<=mid) change(p*2,l,r,v);
if(r>mid) change(p*2+1,l,r,v);
}
void ask(int p,int l,int r)
{
if(t[p].dat)
{
ans[t[p].dat] = 1;
return ;
}
if(t[p].l == t[p].r)
return;
int mid = (t[p].l+t[p].r)/2;
spread(p);
ask(p*2,l,r);
ask(p*2+1,l,r);
}
vector<int>num;
int n;
int main()
{
ios::sync_with_stdio(false);
int T;
cin >> T;
while(T--)
{
cin >> n;
num.clear();
for(int i=1;i<=n;i++)
{
cin >> l[i] >> r[i];
num.push_back(l[i]);
num.push_back(r[i]);
}
sort(num.begin(),num.end());
num.erase(unique(num.begin(),num.end()),num.end());
int m = num.size();
for(int i=1;i<m;i++)
{
if(num[i] - num[i-1] > 1)
num.push_back(num[i-1]+1);
}
sort(num.begin(),num.end());
m = num.size();
build(1,0,m-1);
for(int i=1;i<=n;i++)
{
ans[i] = 0;
int x = lower_bound(num.begin(),num.end(),l[i])-num.begin();
int y = lower_bound(num.begin(),num.end(),r[i])-num.begin();
change(1,x,y,i);
}
int res = 0;
ask(1,0,m-1);
for(int i=1;i<=n;i++)
{
if(ans[i])
res++;
}
cout << res << "
";
}
return 0;
}