CS Round #50 Min Races（nlogn级别的LDS）

 1 #include <iostream>
 2 #include <algorithm>
 3 using namespace std;
 4 
 5 const int N=1e5+10;
 6 struct TnT{
 7     int a,b;
 8 }T[N];
 9 
10 int A[N],B[N];
11 
12 bool cmp(TnT x,TnT y){
13     return x.b<y.b;    
14 }
15 
16 int binsearch(int low,int high,int num){
17     while(low<=high){
18         int mid=(low+high)/2;
19         if(B[mid]>=num) low=mid+1;
20         else high=mid-1;
21     }
22     return low;
23 }
24 
25 int dp(int n){
26     B[1]=A[1];
27     int len=1;
28     for(int i=2;i<=n;i++){
29         if(A[i]<=B[len]) {len++;B[len]=A[i];}
30         else{
31             int pos=binsearch(1,n,A[i]);
32             B[pos]=A[i];
33         }
34     }
35     return len;
36 }
37 
38 int main(){
39     int n,k;
40     cin>>n>>k;
41     for(int i=1;i<=n;i++) cin>>T[i].a>>T[i].b;
42     sort(T+1,T+1+n,cmp);
43     for(int i=1;i<=n;i++) A[i]=T[i].a;
44     cout<<dp(n)<<endl;
45     return 0;
46 }