https://www.luogu.org/problem/P3431
二维偏序经典题，树状数组维护前缀最大值，dp思想。
1 #define bug(x) cout<<#x<<" is "<<x<<endl 2 #define IO std::ios::sync_with_stdio(0) 3 #define ull unsigned long long 4 #include <bits/stdc++.h> 5 #define iter ::iterator 6 #define pa pair<int,ll> 7 #define pp pair<int,pa> 8 using namespace std; 9 #define ll long long 10 #define mk make_pair 11 #define pb push_back 12 #define se second 13 #define fi first 14 #define ls o<<1 15 #define rs o<<1|1 16 const int N=1e5+5; 17 int n,m,q; 18 int mx=1e9; 19 pp p[N]; 20 int c[N]; 21 int low(ll x){ 22 return x&(-x); 23 } 24 void add(int x,int y){ 25 while(x<=q){ 26 c[x]=max(c[x],y); 27 x+=low(x); 28 } 29 } 30 int qu(int x){ 31 int res=0; 32 while(x){ 33 res=max(res,c[x]); 34 x-=low(x); 35 } 36 return res; 37 } 38 int a[N]; 39 int main(){ 40 IO; 41 cin>>n>>m>>q; 42 for(int i=1;i<=q;i++){ 43 cin>>p[i].fi>>p[i].se.fi>>p[i].se.se; 44 a[i]=p[i].se.fi; 45 } 46 sort(a+1,a+1+q); 47 int na=unique(a+1,a+1+q)-a-1; 48 sort(p+1,p+1+q); 49 ll ans=p[1].se.se; 50 int x=lower_bound(a+1,a+1+na,p[1].se.fi)-a; 51 add(x,ans); 52 for(int i=2;i<=q;i++){ 53 int x=lower_bound(a+1,a+1+na,p[i].se.fi)-a; 54 ll res=qu(x)+p[i].se.se; 55 ans=max(ans,res); 56 add(x,res); 57 } 58 printf("%lld ",ans); 59 }