poj 2482 Stars in Your Window 线段树+离散化

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//poj 2482//sep9#include <iostream>#include <algorithm>using namespace std;typedef __int64 INT;typedef pair<pair<INT,INT>,pair<INT,INT> > SEG;//(x,cs),(y1,y2)const int MAXN=10000;INT n,W,H;INT xs[MAXN+10],ys[MAXN+10];INT cs[MAXN+10];INT X[MAXN*2+10],Y[MAXN*2+10];SEG event[MAXN*2+10];int node_value[MAXN*10],node_max[MAXN*10]; void add(INT from,INT to,INT v,INT i,INT l,INT r){if(from<=l&&r<=to){node_value[i]+=v;node_max[i]+=v;return ;}INT m=(l+r)>>1;if(from<=m) add(from,to,v,i*2,l,m);if(m<to) add(from,to,v,i*2+1,m+1,r);node_max[i]=max(node_max[i*2],node_max[i*2+1])+node_value[i];}INT max(INT a,INT b){return a<b?b:a;}int main(){while(scanf("%I64d%I64d%I64d",&n,&W,&H)==3){for(int i=0;i<n;++i){scanf("%I64d%I64d%I64d",&xs[i],&ys[i],&cs[i]);xs[i]*=2,ys[i]*=2;X[i*2]=xs[i]-W;X[i*2+1]=xs[i]+W;Y[i*2]=ys[i]-H;Y[i*2+1]=ys[i]+H-1;}sort(X,X+n*2);sort(Y,Y+n*2);for(int i=0;i<n;++i){event[i*2]=make_pair(make_pair(lower_bound(X,X+n*2,xs[i]-W)-X,cs[i]),                                 make_pair(lower_bound(Y,Y+n*2,ys[i]-H)-Y,lower_bound(Y,Y+n*2,ys[i]+H-1)-Y));  event[i*2+1]=make_pair(make_pair(lower_bound(X,X+n*2,xs[i]+W)-X,-cs[i]),                                 make_pair(lower_bound(Y,Y+n*2,ys[i]-H)-Y,lower_bound(Y,Y+n*2,ys[i]+H-1)-Y));}sort(event,event+n*2);INT ans=0;for(int i=0;i<n*2;++i){add(event[i].second.first,event[i].second.second,event[i].first.second,1,0,n*2);ans=max(ans,node_max[1]);}printf("%I64d\n",ans);}return 0;}

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