POJ1436Horizontally Visible Segments line segment tree + lazy, line segment tree lazy

POJ1436Horizontally Visible Segments line segment tree + lazy, line segment tree lazy

Determine whether three lines are connected. If any two lines are connected, the three lines are connected; open a hash [I] [j] To save the relationship between the I-th line segment and the j-th line segment, before inserting a new line segment, you must first determine whether the line is connected to other line segments before inserting the line segment. PS: note that the x coordinates of all line segments must be sorted first, and then the line segments are inserted in the mature order;

#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>#include <climits>#include <string>#include <iostream>#include <map>#include <cstdlib>#include <list>#include <set>#include <queue>#include <stack>using namespace std;#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1#define maxn 8010int col[maxn*10];bool hash[maxn][maxn];struct bian{    int y1,y2,x;}edge[maxn];int cmp(bian a,bian b){    return a.x<b.x;}void pushdown(int rt){    if(~col[rt])    {        col[rt<<1]=col[rt<<1|1]=col[rt];        col[rt]=-1;    }}void build(int l,int r,int rt){    col[rt]=-1;    if(l==r) return ;    int m=(l+r)>>1;    build(lson);    build(rson);}void update(int L,int R,int cha,int l,int r,int rt){    if(L<=l&&R>=r)    {        col[rt]=cha;        return ;    }    pushdown(rt);    int m=(l+r)>>1;    if(L<=m) update(L,R,cha,lson);    if(R>m) update(L,R,cha,rson);}void query(int L,int R,int cha,int l,int r,int rt){    if(col[rt]!=-1)    {        hash[cha][col[rt]]=hash[col[rt]][cha]=cha;        return ;    }    if(l==r) return ;    int m=(l+r)>>1;    if(L<=m) query(L,R,cha,lson);    if(R>m) query(L,R,cha,rson);}int main(){    int t,n,a,b,c;    scanf("%d",&t);    while(t--)    {        memset(hash,0,sizeof(hash));        int MAX=-1;        scanf("%d",&n);        for(int i=0;i<n;i++)        {            scanf("%d%d%d",&a,&b,&c);            edge[i].y1=a*2;edge[i].y2=b*2;            edge[i].x=c;            MAX=max(MAX,edge[i].y2);        }        sort(edge,edge+n,cmp);        build(0,MAX,1);        for(int i=0;i<n;i++)        {            query(edge[i].y1,edge[i].y2,i,0,MAX,1);            update(edge[i].y1,edge[i].y2,i,0,MAX,1);        }        int ans=0;        for(int i=0;i<n;i++)        {            for(int j=i+1;j<n;j++)            {                if(!hash[i][j]) continue;                for(int k=j+1;k<n;k++)                {                    if(hash[i][k]&&hash[j][k])                    ans++;                }            }        }        printf("%d\n",ans);    }    return 0;}