Luogu P4331 [BOI2004]Sequence 数字序列 (左偏树论文题)

清晰明了%%% Fairycastle的博客

个人习惯把size什么的存在左偏树结点内,这样在外面好写,在里面就是模板(只用修改update).

可以对比一下代码(好像也差不多…)

MY CODE

#include <vector>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int MAXN = 1000005;
struct lt {
	int ls, rs, v, d, sz;
}t[MAXN];
int n, m, l[MAXN], r[MAXN], st[MAXN], a[MAXN], b[MAXN]; //st存栈内根节点编号
inline void upd(int x) {
	if(t[t[x].ls].d < t[t[x].rs].d) swap(t[x].ls, t[x].rs);
	t[x].d = t[t[x].rs].d + 1;
	t[x].sz = t[t[x].ls].sz + t[t[x].rs].sz + 1;
}
int merge(int x, int y) {
    if(!x || !y) return x + y;
    if(t[y].v > t[x].v) swap(x, y);
    t[x].rs = merge(t[x].rs, y);
    upd(x);
    return x;
}
inline int pop(int x) {
    int l = t[x].ls, r = t[x].rs;
    t[x].ls = t[x].rs = t[x].d = 0; t[x].sz = 1;
    return merge(l, r);
}
int main () {
    t[0].d = -1;
	scanf("%d", &n);
	for(int i = 1; i <= n; ++i) scanf("%d", &a[i]), a[i] -= i;
	for(int i = 1; i <= n; ++i) {
		st[++m] = i; l[m] = r[m] = i;
		t[i] = (lt) { 0, 0, a[i], 0, 1 };
		while(m > 1 && t[st[m-1]].v > t[st[m]].v) {
			--m;
			st[m] = merge(st[m], st[m+1]);
			r[m] = r[m+1];
			while(t[st[m]].sz<<1 > r[m]-l[m]+2)
				st[m] = pop(st[m]);
		}
	}
	long long ans = 0;
	for(int i = 1; i <= m; ++i)
		for(int j = l[i]; j <= r[i]; ++j)
			ans += abs(a[j]-(b[j]=t[st[i]].v));
	printf("%lld\n", ans);
	for(int i = 1; i <= n; ++i) printf("%d ", b[i] + i);
}

Other CODE

#include<bits/stdc++.h>
#define ll long long
#define in inline
#define rint register int
#define N 1000010
using namespace std;
int n,m;
int d[N],ls[N],rs[N];
ll a[N],b[N],ans;
struct node{
    int rt,l,r,siz;
    ll w;
}s[N];
in ll read()
{
    ll x=0,f=1; char ch=getchar();
    while(ch<'0'||ch>'9') { if(ch=='-') f=-1; ch=getchar(); }
    while(ch>='0'&&ch<='9') { x=x*10+ch-'0'; ch=getchar(); }
    return x*f;
}
in int merge(int x,int y)
{
    if(x==0||y==0) return x+y;
    if(a[x]<a[y]) swap(x,y);
    rs[x]=merge(rs[x],y);
    if(d[ls[x]]<d[rs[x]]) swap(ls[x],rs[x]);
    d[x]=d[rs[x]]+1;
    return x;
}
in void work()
{
    for(rint i=1;i<=n;i++)
    {
        s[++m]=(node) { i,i,i,1,a[i] };
        while(m>1&&s[m].w<s[m-1].w)
        {
            m--;
            s[m].rt=merge(s[m].rt,s[m+1].rt);
            s[m].siz+=s[m+1].siz; 
            s[m].r=s[m+1].r;
            while(s[m].siz>(s[m].r-s[m].l+1+2)>>1)//向上取整 
            {
                s[m].siz--;
                s[m].rt=merge(ls[s[m].rt],rs[s[m].rt]);
            }
            s[m].w=a[s[m].rt];
        }
    }
    for(rint i=1;i<=m;i++)
        for(rint j=s[i].l;j<=s[i].r;j++) 
            b[j]=s[i].w,ans+=abs(a[j]-b[j]);
}
int main()
{
    d[0]=-1; n=read();
    for(rint i=1;i<=n;i++) a[i]=read()-i;
    work();
    printf("%lld\n",ans);
    for(rint i=1;i<=n;i++) printf("%lld ",b[i]+i);
    return 0;
}