Submission #1152716

#	Time	Username	Problem	Language	Result	Execution time	Memory
1152716		alexdd	Shortcut (IOI16_shortcut)	C++20	38 / 100	2094 ms	5464 KiB

shortcut

#include "shortcut.h"
#include<bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e18;
const int MAXN = 3005;
int n,c;
int a[MAXN];//pozitii
int d[MAXN];
int worst_pref[MAXN],worst_suff[MAXN];
int only_pref[MAXN],only_suff[MAXN];
int inainte[MAXN][MAXN];
bool verif(int lim)
{
    if(only_pref[n] <= lim)
        return 1;
    vector<vector<int>> prec(n+2,vector<int>(n+2,-INF));
    for(int u=1;u<=n;u++)
    {
        for(int v=u+1;v<=n;v++)
        {
            if(a[v] + d[v] - a[u] + d[u] > lim)
            {
                prec[u][v] = a[u] - a[v] + d[u] + d[v];
            }
        }
    }
    for(int u=1;u<=n;u++)
    {
        for(int v=u+1;v<=n;v++)
        {
            prec[u][v] = max(prec[u][v], prec[u+1][v]);
            prec[u][v] = max(prec[u][v], prec[u][v-1]);
        }
    }
    for(int u=n;u>0;u--)
    {
        for(int v=n;v>u;v--)
        {
            prec[u][v] = max(prec[u][v], prec[u+1][v]);
            prec[u][v] = max(prec[u][v], prec[u][v-1]);
        }
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=i+1;j<=n;j++)
        {
            if(c >= a[j]-a[i])
                continue;
            bool bun=1;

            if(i+1<j-1 && prec[i+1][j-1] > lim - (a[j]+c-a[i]))
                bun=0;
            if(inainte[i][j] > lim)
                bun=0;
            if(bun)
                return 1;
        }
    }
    return 0;
}
long long find_shortcut(int32_t cit_n, std::vector<int32_t> l, std::vector<int32_t> citd, int32_t cit_c)
{
    n = cit_n;
    c = cit_c;

    for(int i=2;i<=n;i++)
        a[i] = a[i-1] + l[i-2];
    for(int i=1;i<=n;i++)
    {
        d[i] = citd[i-1];
    }

    worst_pref[0] = -INF;
    for(int i=1;i<=n;i++)
        worst_pref[i] = max(worst_pref[i-1], -a[i] + d[i]);
    worst_suff[n+1] = -INF;
    for(int i=n;i>0;i--)
        worst_suff[i] = max(worst_suff[i+1], a[i] + d[i]);

    only_pref[0] = -INF;
    for(int i=1;i<=n;i++)
        only_pref[i] = max({only_pref[i-1], a[i] + d[i] + worst_pref[i-1], d[i]});
    only_suff[n+1] = -INF;
    for(int i=n;i>0;i--)
        only_suff[i] = max({only_suff[i+1], -a[i] + d[i] + worst_suff[i+1], d[i]});

    for(int i=1;i<=n;i++)
    {
        for(int j=i+1;j<=n;j++)
        {
            if(c >= a[j]-a[i])
                continue;
            bool bun=1;
            int mxm=0;
            mxm = max(mxm, a[i] + worst_pref[i] + c + worst_suff[j] - a[j]);
            mxm = max(mxm, only_pref[i]);
            mxm = max(mxm, only_suff[j]);
            mxm = max(mxm, (int)c);


            for(int u=i+1;u<j;u++)
            {
                mxm = max(mxm, d[u] + worst_pref[i] + min(a[u], a[i] + c + a[j] - a[u]));
            }
            for(int u=i+1;u<j;u++)
            {
                mxm = max(mxm, d[u] + worst_suff[j] + min(-a[u], -a[j] + c + a[u] - a[i]));
            }
            for(int u=i+1;u<j;u++)
                mxm = max(mxm, d[u]);

            inainte[i][j] = mxm;
        }
    }
    
    int st=0,dr=INF,ans=INF;
    while(st<=dr)
    {
        int mij=(st+dr)/2;
        if(verif(mij))
        {
            ans = mij;
            dr = mij-1;
        }
        else
            st = mij+1;
    }
    return ans;
}
/*

4 10
10 20 20
0 40 0 30

output: 80


9 30
10 10 10 10 10 10 10 10
20 0 30 0 0 40 0 40 0

output: 110

*/

Compilation message (stderr)

shortcut.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
shortcut_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3