Submission #228044

#	Time	Username	Problem	Language	Result	Execution time	Memory
228044		AaronNaidu	Ancient Books (IOI17_books)	C++14	50 / 100	163 ms	18936 KiB

books

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int pos[1000001];

ll minimum_walk(vector<int> p, int s) {
    int trueLength = p.size();
    for (int i = 0; i < p.size(); i++)
    {
        pos[p[i]] = i;
    }
    
    for (int i = p.size() - 1; i >= 0; i--)
    {
        if (p[i] == i)
        {
            trueLength--;
        }
        else
        {
            break;
        }
    }
    ll toRet = 0;
    int startPoint = 0;
    int maxSoFar = -1;
    int groups = 0;
    for (int i = 0; i < trueLength; i++)
    {
        toRet += abs(i - p[i]);
        maxSoFar = max(maxSoFar, p[i]);
        if (maxSoFar == i)
        {
        //    cout << "Breaking at " << i << "\n";
            groups++;
            if (i < trueLength - 1)
            {
               // cout << "Adding " << abs(pos[startPoint] - (i+1)) << " for travelling\n";
                //toRet += abs(pos[startPoint] - (i+1));
                startPoint = i+1;
            }
            else
            {
                //cout << "Adjustment adding " << abs(startPoint - p[startPoint]) << " for " << startPoint << "\n";
                //toRet += abs(pos[startPoint] - p[pos[startPoint]]);
            }
            
        }
    }
    //cout << "Adding " << startPoint << " at end\n";
    //toRet += startPoint;
    if (groups == 0)
    {
        groups++;
    }
    
    toRet += 2 * (groups - 1);
    return toRet;
}

Compilation message (stderr)

books.cpp: In function 'll minimum_walk(std::vector<int>, int)':
books.cpp:9:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < p.size(); i++)
                     ~~^~~~~~~~~~
books.cpp:26:9: warning: variable 'startPoint' set but not used [-Wunused-but-set-variable]
     int startPoint = 0;
         ^~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30