제출 #1285648

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1285648		Faisal_Saqib	Money (IZhO17_money)	C++20	100 / 100	614 ms	67036 KiB

money

#include <bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int dp[N];
int a[N],valid[N],nxt[N],fen[N];
// void add()
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin>>n;
    int vt=1e6;
    set<int> vis={vt+1};
    nxt[0]=vt+1;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        auto it=vis.upper_bound(a[i]);
        nxt[i]=*it;
        vis.insert(a[i]);
        valid[i]=i-1;
        if(a[i-1]<=a[i])
        {
            valid[i]=valid[i-1];
        }
    }
    dp[0]=0;
    deque<int> cur;
    cur.push_back(0);
    // int mip=0;
    for(int i=1;i<=n;i++)
    {
        // dp[cur[0]] <= dp[cur[1]] <= .. 
        dp[i]=i;
        // dp[i]= min(dp[ip])  valid[i]-1<=ip  and not element in prefix ip is in the range [a[ip+1],a[i]]
        // dp[i] = min(dp[ip]) valid[i]<=ip<=i-1 and nxt[ip]>=a[i]
        // for(int ip=i-1;ip>=valid[i];ip--)
        // {   
        //     if(nxt[ip+1]>=a[i])
        //     {
        //         dp[i]=min(dp[i],dp[ip]+1);
        //     }
        // }
        // add dp[i] at nxt[i]
        int s=valid[i]-1,e=i;
        while(s+1<e)
        {
            int mid=(s+e)/2;
            if(nxt[mid+1]>=a[i])
            {
                e=mid;
            }
            else
            {
                s=mid;
            }
        }
        if(e==i)
        {
            dp[i]=i;
        }
        else
        {
            // we need min dp
            // [e..i-1]
            auto it=lower_bound(begin(cur),end(cur),e);
            dp[i]=min(dp[i],dp[*it]+1);
        }
        while(cur.size()>0 and dp[cur.back()]>=dp[i])
        {
            cur.pop_back();
        }
        cur.push_back(i);
        // nxt[valid[i]] <= nxt[valid[i+1]] <= .. <= nxt[i]
    }
    cout<<dp[n]<<endl;
}

• Subtask 1: 9 / 9
• Subtask 2: 16 / 16
• Subtask 3: 20 / 20
• Subtask 4: 55 / 55