[Explanations] AcWing 110. sunscreen (popular title)

[Explanations] AcWing 110. sunscreen (popular title)

AcWing 110. Sun

You have not used the new OJ

Hey Shui title.

Topic is one-dimensional coordinate axes given multiple segments of a given number of points, resulting contribution to the segment points, points can be repeated and asked greatest contribution

Template questions, mainly to give notice when the point is not necessarily different from each other, so to record it. Carefully set to go heavy.

//@winlere
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<set>

using namespace std;  typedef long long ll;
inline int qr(){
      register int ret=0,f=0;
      register char c=getchar();
      while(c<48||c>57)f|=c==45,c=getchar();
      while(c>=48&&c<=57) ret=ret*10+c-48,c=getchar();
      return f?-ret:ret;
}

const int maxn=2505;
struct L{
      int l,r;
      L(){l=r=0;}
      L(const int&a,const int&b){l=a;r=b;}
      inline bool operator <(const L&a)const{return r==a.r?l>a.l:r<a.r;}
}data[maxn];
int cnt[1001],n,m,ans;
set <int> s;

int main(){
      n=qr();m=qr();
      for(register int t=1,t1,t2;t<=n;++t)
        t1=qr(),t2=qr(),data[t]=L(t1,t2);
      for(register int t=1,t1,t2;t<=m;++t){
        t1=qr();t2=qr();
        cnt[t1]+=t2;
        s.insert(t1);
      }
      sort(data+1,data+n+1);
      for(register int t=1;t<=n;++t){
        set<int>::iterator a=s.lower_bound(data[t].l);
        if(a==s.end()||*a>data[t].r) continue;
        if(--cnt[*a]<=0) s.erase(a);
        ++ans;
      }
      printf("%d\n",ans);
      return 0;
}