离散化之后,枚举所有的可能的选择点x,然后查询有多少个区间的l>x,多少个r<x,然后剩下的就是满足温度的.
#include<iostream>
#include<cstring>
#include<string>
#include<math.h>
#include<algorithm>
#include<vector>
#include<queue>
#include<stack>
#include<map>
#include<set>
//#pragma GCC optimize(2)
#define eps 1e-9
#define fi first
#define se second
#define pb push_back
#define db double
#define ll long long
#define PII pair<int,int >
#define cin(x) scanf("%d",&x)
#define cout(x) printf("%d ",x)
#define mem(a,b) memset(a,b,sizeof(a))
#define IOS std::ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
#define int ll
using namespace std;
const int N = 5e6,M = 2000;
const int mod = 1e9+7;
const int inf = 0x3f3f3f3f;
const double pai = acos(-1);
int T,n,m,k;
PII va[N];
int vb[N],vc[N];
vector<int > v;
int get(int x)
{
return lower_bound(v.begin(),v.end(),x)-v.begin()+1;
}
signed main()
{
IOS;
int a,b,c;
cin>>n>>a>>b>>c;
for(int i=1;i<=n;i++) cin>>va[i].fi>>va[i].se;
for(int i=1;i<=n;i++) v.pb(va[i].fi),v.pb(va[i].se);
sort(v.begin(),v.end());
v.erase(unique(v.begin(),v.end()),v.end());
vector<int > vl,vr;
for(int i=1;i<=n;i++)
{
vl.pb(get(va[i].fi));
vr.pb(get(va[i].se));
}
sort(vl.begin(),vl.end());
sort(vr.begin(),vr.end());
int maxn = 0;
for(int i=1;i<=v.size();i++)
{
int t1 = n-(upper_bound(vl.begin(),vl.end(),i)-vl.begin()+1-1);
int t2 = lower_bound(vr.begin(),vr.end(),i)-vr.begin()+1-1;
maxn = max(maxn,t1*c+t2*a+b*(n-t1-t2));
}
cout<<maxn;
return 0;
}