P2234 [HNOI2002]营业额统计(50分。。。。)

50

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>

#define N 50007
#define inf 0x7fffffff

using namespace std;
int n,a[N],d[N],ans;

struct Data
{
    int x,ord;
}data[N];

struct tree
{
    int l,r,mn,mx,sum;
}tr[N<<2];

bool cmp(Data a,Data b){return a.x<b.x;}

void build(int now,int l,int r)
{
    tr[now].l=l;tr[now].r=r;tr[now].mn=inf-1;tr[now].mx=-1;
    if(l==r) return;
    int mid=(l+r)>>1;
    build(now<<1,l,mid);build(now<<1|1,mid+1,r);
}

inline void push_up(int now)
{
    tr[now].sum=tr[now<<1].sum+tr[now<<1|1].sum;
    tr[now].mx=max(tr[now<<1].mx,tr[now<<1|1].mx);
    tr[now].mn=min(tr[now<<1].mn,tr[now<<1|1].mn);
}

void modify(int now,int x)
{
    if(tr[now].l==tr[now].r && tr[now].l==x)
    {
        tr[now].sum=1;
        tr[now].mx=x;
        tr[now].mn=x;
        return;
    }
    int mid=(tr[now].l+tr[now].r)>>1;
    if(x>mid) modify(now<<1|1,x);
    if(x<=mid)modify(now<<1,x);
    push_up(now);
}

int querymx(int now,int l,int r)
{
    if(r<l) return -1;
    if(tr[now].sum==0) return -1;
    if(tr[now].l==l&&tr[now].r==r) return tr[now].mx;
    int mid=(tr[now].l+tr[now].r)>>1;
    if(r<=mid) return querymx(now<<1,l,r);
    else if(l>mid) return querymx(now<<1|1,l,r);
    else return max(querymx(now<<1,l,mid),querymx(now<<1|1,mid+1,r));
}

int querymn(int now,int l,int r)
{
    if(r<l) return -1;
    if(tr[now].sum==0) return inf-1;
    if(tr[now].l==l&&tr[now].r==r) return tr[now].mn;
    int mid=(tr[now].l+tr[now].r)>>1;
    if(r<=mid) return querymn(now<<1,l,r);
    else if(l>mid) return querymn(now<<1|1,l,r);
    else return min(querymn(now<<1,l,mid),querymn(now<<1|1,mid+1,r));
}

int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        if(scanf("%d",&a[i])==EOF) a[i]=0;
        data[i].ord=i;data[i].x=a[i];
    }
    sort(data+1,data+n+1,cmp);
    int ord=1;d[1]=data[1].x;a[data[1].ord]=ord;
    for(int i=2;i<=n;i++)
    {
        if(data[i].x!=data[i-1].x) ord++;
        a[data[i].ord]=ord;d[ord]=data[i].x;
    }
    build(1,1,ord);
    ans=d[a[1]];modify(1,a[1]);
    for(int i=2;i<=n;i++)
    {
        int x=querymx(1,1,a[i]-1),y=querymn(1,a[i],n),tmp=inf;
        if(x!=-1) tmp=min(tmp,d[a[i]]-d[x]);
        if(y!=inf-1) tmp=min(tmp,d[y]-d[a[i]]);
        ans+=tmp;
        modify(1,a[i]);
    }
    printf("%d\n",ans);
    return 0;
}

AC的

#include<cstdio>
#include<algorithm>
#include<map>
#define N 50010
#define inf 0x7fffffff
using namespace std;

int n,a[N],d[N];

struct Data{
    int x,ord;
}data[N];

bool cmp(Data a,Data b){
    return a.x<b.x;
}

struct node{
    int l,r,sum,mx,mn;
}t[N<<2];

void pushup(int rt){
    t[rt].sum=t[rt<<1].sum+t[rt<<1|1].sum;
    t[rt].mx=max(t[rt<<1].mx,t[rt<<1|1].mx);
    t[rt].mn=min(t[rt<<1].mn,t[rt<<1|1].mn);
}

void build(int rt,int l,int r){
    t[rt].l=l;t[rt].r=r;t[rt].mx=-1;t[rt].mn=inf-1;
    if(l==r) return;
    int mid=(l+r)>>1;
    if(l<=mid) build(rt<<1,l,mid);
    if(r>mid) build(rt<<1|1,mid+1,r);
}

void modify(int rt,int pos){
    if(t[rt].l==t[rt].r){
        t[rt].sum=1;
        t[rt].mn=t[rt].l;
        t[rt].mx=t[rt].l;
        return;
    }
    int mid=(t[rt].l+t[rt].r)>>1;
    if(pos<=mid) modify(rt<<1,pos);
    if(pos>mid) modify(rt<<1|1,pos);
    pushup(rt);
}

int querymx(int rt,int l,int r){
    if(r<l) return -1;
    if(t[rt].sum==0) return -1;
    if(l<=t[rt].l&&t[rt].r<=r) return t[rt].mx;
    int mid=(t[rt].l+t[rt].r)>>1,ret=-2;
    if(l<=mid) ret=max(ret,querymx(rt<<1,l,r));
    if(r>mid) ret=max(ret,querymx(rt<<1|1,l,r));
    return ret;
}

int querymn(int rt,int l,int r){
    if(r<l) return inf-1;
    if(t[rt].sum==0) return inf-1;
    if(l<=t[rt].l&&t[rt].r<=r) return t[rt].mn;
    int mid=(t[rt].l+t[rt].r)>>1,ret=inf;
    if(l<=mid) ret=min(ret,querymn(rt<<1,l,r));
    if(r>mid) ret=min(ret,querymn(rt<<1|1,l,r));
    return ret;
}

int main(){
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        if(scanf("%d",&a[i])==EOF) a[i]=0;
        data[i].ord=i;data[i].x=a[i];
    }
    sort(data+1,data+1+n,cmp);
    int ord=1;d[1]=data[1].x;a[data[1].ord]=ord;
    for(int i=2;i<=n;i++){
        if(data[i].x!=data[i-1].x) ord++;
        a[data[i].ord]=ord;d[ord]=data[i].x;
    }
    build(1,1,ord);
    int ans=d[a[1]];modify(1,a[1]);
    for(int i=2;i<=n;i++){
        int x=querymx(1,1,a[i]-1),y=querymn(1,a[i],n),tmp=inf;
        if(x!=-1) tmp=min(tmp,d[a[i]]-d[x]);
        if(y!=inf-1) tmp=min(tmp,d[y]-d[a[i]]);
        ans+=tmp;
        modify(1,a[i]);
    }
    printf("%d\n",ans);
    return 0;
}