HDU/HDOJ----4302 Holedox Eating

多校第一场比较水的一道题，用线段树查找离要求点最近的目标。当时很快就有思路了，但是一直想拿ZKW版线段树写，由于没有完全掌握其精髓，当场没有做出来，赛后用常规版写的，而且写的比较丑陋……

#include <iostream>#include <cstdio>#include <cmath>#define lson l,mid,rt<<1#define rson mid+1,r,rt<<1^1#define ll long long#define N 100005#define inf 1e9#define linf 1e9#define rinf -1using namespace std;struct node{    int left,right;    int num,lmost,rmost;}seg[3*N];int min(int a,int b) { return a<b?a:b; }int max(int a,int b) { return a>b?a:b; }void segtree_build(int l,int r,int rt){    //cout<<"<"<<l<<","<<r<<">"<<endl;    seg[rt].left=l,seg[rt].right=r;    seg[rt].num=0,seg[rt].lmost=linf,seg[rt].rmost=rinf;    if(l==r) return ;    int mid=(l+r)>>1;    segtree_build(lson);    segtree_build(rson);}node segtree_query(int L,int R,int l,int r,int rt){    node ans,tl,tr;    ans.lmost=linf,ans.rmost=rinf;    if(L<=l&&r<=R){        ans.lmost=min(ans.lmost,seg[rt].lmost);        ans.rmost=max(ans.rmost,seg[rt].rmost);        return ans;    }    int mid=(seg[rt].left+seg[rt].right)>>1;    if(L<=mid){        tl=segtree_query(L,R,lson);        ans.lmost=min(ans.lmost,tl.lmost);        ans.rmost=max(ans.rmost,tl.rmost);    }    if(R>mid){        tr=segtree_query(L,R,rson);        ans.lmost=min(ans.lmost,tr.lmost);        ans.rmost=max(ans.rmost,tr.rmost);    }    return ans;}void segtree_insert(int p,int rt,int index){    seg[rt].num+=index;    if(seg[rt].num==0) seg[rt].lmost=linf,seg[rt].rmost=rinf;    if(seg[rt].left==p&&seg[rt].right==p){        if(seg[rt].num) seg[rt].lmost=p,seg[rt].rmost=p;        return ;    }    int mid=(seg[rt].left+seg[rt].right)>>1;    if(p<=mid) segtree_insert(p,rt<<1,index);    else segtree_insert(p,rt<<1^1,index);    if(seg[rt].num){        seg[rt].lmost=min(seg[rt<<1].lmost,seg[rt<<1^1].lmost);        seg[rt].rmost=max(seg[rt<<1].rmost,seg[rt<<1^1].rmost);    }}void segtree_print(int L){    for(int i=1;i<=L*2;i*=2){        for(int j=0;j<i;j++){            int pos=i+j;            printf("<%d,%d> ",seg[pos].left,seg[pos].right);            if(seg[pos].lmost==linf) printf("no ");            else printf("%d ",seg[pos].lmost);            if(seg[pos].rmost==rinf) printf("no ");            else printf("%d ",seg[pos].rmost);            printf("%d| ",seg[pos].num);        }        printf("\n");        for(int k=0;k<80;k++)            printf("-");        printf("\n");    }}int main(){    //freopen("in.in","r",stdin);    int T,L,n,Case=1;    int lp,rp,ld,rd;    scanf("%d",&T);    while(T--){        scanf("%d%d",&L,&n);        segtree_build(0,L,1);        //segtree_print(L);        //cout<<"segtree_build done!"<<endl;        int lst=0,pos=0,ope,p;        ll ans=0;        while(n--){            scanf("%d",&ope);            if(ope){                lp=segtree_query(0,pos,0,L,1).rmost; ld=(lp==rinf?inf:abs(lp-pos)); //if(lp==inf) cout<<"no"<<' '; else cout<<"lp="<<lp<<' ';                rp=segtree_query(pos,L,0,L,1).lmost; rd=(rp==linf?inf:abs(rp-pos)); //if(rp==inf) cout<<"no"<<endl; else cout<<"rp="<<rp<<endl;                if(ld==inf&&rd==inf) continue;                else if(ld<rd||(ld==rd&&lst==-1)){                    pos=lp,lst=-1,ans+=(ll)ld;                    segtree_insert(pos,1,-1);                    //segtree_print(L);                    //cout<<"delete "<<pos<<" done!"<<endl;                }                else if(ld>rd||(ld==rd&&lst==1)){                    pos=rp,lst=1,ans+=(ll)rd;                    segtree_insert(pos,1,-1);                    //segtree_print(L);                    //cout<<"delete "<<pos<<" done!"<<endl;                }                else if(ld==rd&&lst==0){                    segtree_insert(pos,1,-1);                    //segtree_print(L);                    //cout<<"delete "<<pos<<" done!"<<endl;                }                //cout<<"pos="<<pos<<' '<<"lst="<<lst<<' '<<"ans="<<ans<<endl;            }            else{                scanf("%d",&p);                segtree_insert(p,1,1);                //segtree_print(L);                //cout<<"insert "<<p<<" done!"<<endl;            }        }        printf("Case %d: %lld\n",Case++,ans);    }    return 0;}