Submission #330455

#	Time	Username	Problem	Language	Result	Execution time	Memory
330455		Ruxandra985	Climbers (RMI18_climbers)	C++14	100 / 100	295 ms	195948 KiB

climbers

#include <bits/stdc++.h>

using namespace std;
int n;
long long vinit[5010];
long long dp[25000000];
priority_queue <pair <long long , int> > h;


int encode (int x , int y){

    x--;
    y--;
    return x * n  + y;

}

pair <int , int> decode (int cod){
    return make_pair(cod / n + 1 , cod % n + 1);
}

void muchie (int x1 , int y1 , int x2 , int y2 , long long cost){

    int nod , vecin;

    nod = encode(x1 , y1);
    vecin = encode(x2 , y2);

    if (dp[vecin] > dp[nod] + cost){
        dp[vecin] = dp[nod] + cost;
        h.push(make_pair(-dp[vecin] , vecin));
    }

}
int main()
{
    FILE *fin = stdin;
    FILE *fout = stdout;
    int i , ers , nod , j;
    long long cost;
    pair <int , int> actual;
    fscanf (fin,"%d",&n);
    for (i = 1 ; i <= n ; i++)
        fscanf (fin,"%lld",&vinit[i]);


    ers = 0;

    for (i = 2 ; i < n ; i++){
        if ((vinit[i - 1] <= vinit[i] && vinit[i] <= vinit[i + 1]) || (vinit[i - 1] >= vinit[i] && vinit[i] >= vinit[i + 1]))
            ers++; /// il stergi pe vinit[i]
        else vinit[i - ers] = vinit[i];
    }

    vinit[n - ers] = vinit[n];
    n -= ers;

    /// acum vinit ul e "condensat"

    for (i = 0 ; i < n * n ; i++)
        dp[i] = 2000000000000000000;

    dp[encode(1 , n - 1)] = 0;

    h.push(make_pair(0 , encode(1 , n - 1)));

    while (!h.empty()){
        cost = -h.top().first;
        nod = h.top().second;
        h.pop();

        actual = decode(nod);

        if (dp[nod] != cost)
            continue;

        i = actual.first;
        j = actual.second;

        if (i == j || i == j + 1){
            fprintf (fout,"%lld",cost);
            return 0;
        }

        /// ------------------------------------------------------------------------

        if (j != 1 && vinit[i] == vinit[j])
            muchie (i , j , i , j - 1 , 0);


        if (j != n && vinit[i] == vinit[j + 1])
            muchie (i , j , i , j + 1 , 0);

        if (vinit[j] < vinit[j + 1]){ /// segm e crescator

            if (i != n){ /// ma duc in nodul i + 1, deci nu parasesc segm

                if (vinit[i + 1] > vinit[i] && vinit[i + 1] <= vinit[j + 1]){

                    muchie (i , j , i + 1 , j , vinit[i + 1] - vinit[i]); /// se pastreaza segmentul

                }
                else if (vinit[i + 1] < vinit[i] && vinit[i + 1] >=  vinit[j]){
                    muchie (i , j , i + 1 , j , vinit[i] - vinit[i + 1]);
                }


            }

            if (i != 1){ /// ma duc in nodul i - 1, raman pe acelasi segm

                if (vinit[i - 1] > vinit[i] && vinit[i - 1] <= vinit[j + 1]){

                    muchie (i , j , i - 1 , j , vinit[i - 1] - vinit[i]); /// se pastreaza segmentul

                }
                else if (vinit[i - 1] < vinit[i] && vinit[i - 1] >=  vinit[j]){
                    muchie (i , j , i - 1 , j , vinit[i] - vinit[i - 1]);
                }

            }

            /// --------------------------------------------------

            /// sunt intre j si j + 1

            /// vreau sa ma mut in j, adc cobor
            if (i != n && vinit[i] > vinit[i + 1] && vinit[i] - vinit[i + 1] >= vinit[i] - vinit[j]){
                muchie (i , j , j , i , vinit[i] - vinit[j]);
            }

            if (i != 1 && vinit[i] > vinit[i - 1] && vinit[i] - vinit[i - 1] >= vinit[i] - vinit[j]){
                muchie (i , j , j , i - 1 , vinit[i] - vinit[j]);
            }

            /// in j + 1 , adc urc

            if (i != n && vinit[i] < vinit[i + 1] && vinit[i + 1] - vinit[i] >= vinit[j + 1] - vinit[i]){
                muchie (i , j , j + 1 , i , vinit[j + 1] - vinit[i]);
            }

            if (i != 1 && vinit[i] < vinit[i - 1] && vinit[i - 1] - vinit[i] >= vinit[j + 1] - vinit[i]){
                muchie (i , j , j + 1 , i - 1 , vinit[j + 1] - vinit[i]);
            }

        }
        else { /// segm e descrescator


            if (i != n){ /// ma duc in nodul i + 1, deci nu parasesc segm

                if (vinit[i + 1] > vinit[i] && vinit[i + 1] <= vinit[j]){

                    muchie (i , j , i + 1 , j , vinit[i + 1] - vinit[i]); /// se pastreaza segmentul

                }
                else if (vinit[i + 1] < vinit[i] && vinit[i + 1] >= vinit[j + 1]){
                    muchie (i , j , i + 1 , j , vinit[i] - vinit[i + 1]);
                }


            }

            if (i != 1){ /// ma duc in nodul i - 1, raman pe acelasi segm

                if (vinit[i - 1] > vinit[i] && vinit[i - 1] <= vinit[j]){

                    muchie (i , j , i - 1 , j , vinit[i - 1] - vinit[i]); /// se pastreaza segmentul

                }
                else if (vinit[i - 1] < vinit[i] && vinit[i - 1] >= vinit[j + 1]){
                    muchie (i , j , i - 1 , j , vinit[i] - vinit[i - 1]);
                }

            }

            /// --------------------------------------------------

            /// sunt intre j si j + 1

            /// vinitreau sa ma mut in j, adc URC


            if (i != n && vinit[i] < vinit[i + 1] && vinit[i + 1] - vinit[i] >= vinit[j] - vinit[i]){
                muchie (i , j , j , i , vinit[j] - vinit[i]);
            }

            if (i != 1 && vinit[i] < vinit[i - 1] && vinit[i - 1] - vinit[i] >= vinit[j] - vinit[i]){
                muchie (i , j , j , i - 1 , vinit[j] - vinit[i]);
            }

            /// vinitreau sa ma duc in j + 1 adica cobor

            if (i != n && vinit[i] > vinit[i + 1] && vinit[i] - vinit[i + 1] >= vinit[i] - vinit[j + 1]){
                muchie (i , j , j + 1 , i , vinit[i] - vinit[j + 1]);
            }

            if (i != 1 && vinit[i] > vinit[i - 1] && vinit[i] - vinit[i - 1] >= vinit[i] - vinit[j + 1]){
                muchie (i , j , j + 1 , i - 1 ,vinit[i] - vinit[j + 1]);
            }

        }


    }

    fprintf (fout,"NO");

    return 0;
}

Compilation message (stderr)

climbers.cpp: In function 'int main()':
climbers.cpp:42:12: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   42 |     fscanf (fin,"%d",&n);
      |     ~~~~~~~^~~~~~~~~~~~~
climbers.cpp:44:16: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   44 |         fscanf (fin,"%lld",&vinit[i]);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 50 / 50