Submission #262304

#	Time	Username	Problem	Language	Result	Execution time	Memory
262304		stoyan_malinin	Shortcut (IOI16_shortcut)	C++14	0 / 100	0 ms	384 KiB

shortcut

#include "shortcut.h"
//#include "grader.cpp"

#include <iostream>
#include <deque>

using namespace std;

const int MAXN = 3005;
const long long inf = 1e16 + 5;

int n;
long long c;
vector <int> l, d;

long long pref[MAXN];
pair <long long, long long> maxMid[MAXN][MAXN];
pair <long long, long long> maxL[MAXN], maxR[MAXN];

long long getDist(int l, int r)
{
    if(l>r) swap(l, r);
    if(l==r) return 0;

    if(l==0) return pref[r-1];
    return pref[r-1] - pref[l-1];
}
/*
long long eval22(int start, int finish)
{
    long long answer = 0;

    deque <int> dq;
    long long maxBroken = -inf;

    for(int i = start;i<=finish;i++)
    {
        while(dq.empty()==false && getDist(dq.front(), i)>getDist(start, dq.front())+getDist(i, finish)+c)
        {
            maxBroken = max(maxBroken, d[dq.front()]+getDist(start, dq.front()));
            dq.pop_front();
        }
        while(dq.empty()==false && getDist(dq.back(), i)+d[dq.back()]<=d[i]) dq.pop_back();

        answer = max(answer, maxBroken+getDist(i, finish)+c+d[i]);
        if(dq.empty()==false) answer = max(answer, getDist(dq.front(), i)+d[dq.front()]+d[i]);

        dq.push_back(i);
    }

    return answer;
}
*/

long long eval22(int start, int finish)
{
    long long maxDist = 0;
    for(int i = start;i<=finish;i++)
    {
        for(int j = i+1;j<=finish;j++)
        {
            long long dist = d[i] + d[j];
            dist += min(getDist(i, j), getDist(start, i) + getDist(j, finish) + c);

            maxDist = max(maxDist, dist);
        }
    }

    return maxDist;
}

long long findMax(vector <long long> v)
{
    long long maxVal = 0;
    for(long long x: v) maxVal = max(maxVal, x);

    return maxVal;
}

long long evalShortcut(int start, int finish)
{
    long long val_11 = maxL[start].second;
    long long val_33 = maxR[finish].second;
    long long val_13 = maxL[start].first + min(c, getDist(start, finish)) + maxR[finish].first;
    long long val_12 = maxL[start].first + maxMid[start][finish].first; //O(n)
    long long val_23 = maxR[finish].first + maxMid[start][finish].second; //O(n)
    long long val_22 = eval22(start, finish); //O(n^2)

    cout << "maxMid: " << maxMid[start][finish].first << " " << maxMid[start][finish].second << '\n';
    cout << "val_11: " << val_11 << '\n';
    cout << "val_33: " << val_33 << '\n';
    cout << "val_13: " << val_13 << '\n';
    cout << "val_12: " << val_12 << '\n';
    cout << "val_23: " << val_23 << '\n';
    cout << "val_22: " << val_22 << '\n';

    return findMax({val_11, val_12, val_13, val_22, val_23, val_33});
}

void init()
{
     pref[0] = l[0];
    for(int i = 1;i<n-1;i++) pref[i] = pref[i-1] + l[i];

    maxL[0] = {d[0], d[0]};
    for(int i = 1;i<n;i++)
        maxL[i] = {max(d[i]*1LL, maxL[i-1].first + getDist(i-1, i)),
                   max(maxL[i-1].second, maxL[i-1].first + getDist(i-1, i) + d[i])};

    maxR[n-1] = {d[n-1], d[n-1]};
    for(int i = n-2;i>=0;i--)
        maxR[i] = {max(d[i]*1LL, maxR[i+1].first + getDist(i, i+1)),
                   max(maxR[i+1].second, maxR[i+1].first + getDist(i, i+1) + d[i])};

    for(int i = 0;i<n;i++)
        for(int j = i;j<n;j++)
            maxMid[i][j] = {0, 0};

    for(int i = 0;i<n;i++)
    {
        for(int j = i;j<n;j++)
        {
            for(int p = i;p<=j;p++)
            {
                //left
                maxMid[i][j].first = max(maxMid[i][j].first, min(getDist(i, p), getDist(p, j)+c) + ((p==i)?0:d[p]));

                //right
                maxMid[i][j].second = max(maxMid[i][j].second, min(getDist(p, j), getDist(i, p)+c) + ((p==j)?0:d[p]));
            }
        }
    }

    /*
    for(int j = 0;j<n;j++)
    {
        int ptr = j;
        long long maxNormal = 0;

        for(int i = j;i>=0;i--)
        {
            maxMid[i][j].second = 0;
            while(ptr-1>=i && getDist(ptr-1, j)<=getDist(i, ptr-1)+c)
            {
                ptr--;
                maxNormal = max(maxNormal, getDist(ptr, j) + d[ptr]);
            }

            maxMid[i][j].second = max(maxMid[i][j].second, maxNormal);
        }
    }

    for(int i = 0;i<n;i++)
    {
        for(int j = i;j<n;j++)
        {
            pair <long long, long long> newVal;
            newVal.first = max(maxMid[i][j].first, maxMid[i][j].second+c);
            newVal.second = max(maxMid[i][j].second, maxMid[i][j].first+c);

            //maxMid[i][j] = newVal;
        }
    }
    */
}

long long find_shortcut(int _n, vector <int> _l, vector <int> _d, int _c)
{
    n = _n;
    l = _l;
    d = _d;
    c = _c;
    init();

    long long answer = inf;
    for(int i = 0;i<n;i++)
    {
        for(int j = i+1;j<n;j++)
        {
            cout << i << " ---- " << j << '\n';

            long long val = evalShortcut(i, j);
            answer = min(answer, val);

            //if(val==100) cout << " KKKKKKKKKKKKKKKKKKK " << '\n';
        }
    }

    return answer;
}
/*
4 10
10 20 20
0 40 0 30

9 30
10 10 10 10 10 10 10 10
20 0 30 0 0 40 0 40 0
*/

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• Subtask 2: 0 / 14
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