BZOJ 1537 二维偏序

 #include <iostream>
 #include <cstring>
 #include <cstdio>
 #include <algorithm>
 #include <map>
 using namespace std;
 const int Maxn=;
 int n,m,k,c[Maxn],F[Maxn];
 map<int,int> M;
 struct Info{int x,y,z;}P[Maxn];
 inline bool cmp(Info A,Info B) {return A.x<B.x || (A.x==B.x && A.y<B.y);}
 inline int Max(int x,int y) {return x>y?x:y;}
 inline int Lowbit(int x) {return x&(-x);}
 inline int Query(int x){int Ret=; for (int i=x;i;i-=Lowbit(i)) Ret=Max(Ret,c[i]); return Ret;}
 inline void Update(int x,int y) {for (int i=x;i<=k;i+=Lowbit(i)) c[i]=Max(c[i],y);}
 int main()

 {
     scanf("%d%d%d",&n,&m,&k);
     for (int i=;i<=k;i++) scanf("%d%d%d",&P[i].x,&P[i].y,&P[i].z),M[P[i].y]=;
     int Cnt=; sort(P+,P+k+,cmp);
     for (map<int,int>::iterator it=M.begin();it!=M.end();it++) it->second=++Cnt;
     for (int i=;i<=k;i++) P[i].y=M[P[i].y];
     for (int i=;i<=k;i++)
     {
         F[i]=Query(P[i].y)+P[i].z;
         Update(P[i].y,F[i]);
     }
     int Ans=;
     for (int i=;i<=k;i++) Ans=Max(Ans,F[i]);
     printf("%d\n",Ans);
     return ;
 }

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