Baltic2014 sequence

Problem Description

Input Format

Output Format

An integer R

Sample input

7
9
4
8
20
14
15
18

Sample Output

13

data range

Z are asking sequence 6,7,8,13,14,15,18.
R & lt = 13 is

Detailed analytical & leftist tree

IOI2005 National Team Yellow paper source of the river

Code

#include <iostream>
#include <cstdio>
#define N 1000002
using namespace std;
int n,i,j,a[N],son[N][2],fa[N],dis[N],num[N],l[N],r[N],q[N],top;
long long val[N];
long long abs(long long x)
{
    return x>0?x:-x;
}
int merge(int x,int y)
{
    if(x==0) return y;
    if(y==0) return x;
    if(val[x]<val[y]||(val[x]==val[y]&&x>y)) swap(x,y);
    son[x][1]=merge(son[x][1],y);
    num[x]=num[son[x][0]]+num[son[x][1]]+1;
    if(dis[son[x][0]]<dis[son[x][1]]) swap(son[x][0],son[x][1]);
    fa[son[x][0]]=fa[son[x][1]]=fa[x]=x;
    dis[x]=dis[son[x][1]]+1;
    return x;
}
void pop(int x)
{
    fa[son[x][0]]=son[x][0];
    fa[son[x][1]]=son[x][1];
    fa[x]=merge(son[x][0],son[x][1]);
}
int main()
{
    cin>>n;
    for(i=1;i<=n;i++){
        cin>>val[i];
        val[i]-=i;
        a[i]=val[i];
    }
    val[0]=-1;
    for(i=1;i<=n;i++){
        q[++top]=i;
        l[top]=r[top]=i;
        num[i]=1;
        while(top>1&&val[q[top-1]]>val[q[top]]){
            q[top-1]=merge(q[top-1],q[top]);
            top--;
            r[top]=i;
            while(num[q[top]]>(r[top]-l[top]+2)/2) pop(q[top]),q[top]=fa[q[top]];
        }
    }
    long long ans=0;
    for(i=1;i<=top;i++){
        for(j=l[i];j<=r[i];j++){
            ans+=abs(a[j]-val[q[i]]);
        }
    }
    cout<<ans<<endl;
    return 0;
}