ants.cpp

#include <iostream>
 
#include <vector>
#include <algorithm>
 
using namespace std;
 
class ant_info {
public:
    int pos;
    char dir;
 
    ant_info(int pos, char dir) : pos(pos), dir(dir) {}
 
    static bool cmp(const ant_info& fst, const ant_info& snd)
    {
        return fst.pos < snd.pos;
    }
};
 
int main()
{
    vector<ant_info> ants;
    int maxl;
    int maxr;
    int startl;
    int startr;
    int length;
    int n;
    int pos;
    int dist;
    char dir;
 
    while (cin >> length >> n)
    {
        ants = vector<ant_info>();
        maxl = maxr = -1;
        startl = startr = -1;
        size_t i;
        for (i = 0; i < n; i++)
        {
            cin >> pos >> dir;
 
            ants.push_back(ant_info(pos, dir));
            if (dir == 'L') {
                if (pos > maxl) {
                    maxl = pos;
                }
            } else {
                dist = length - pos;
                if (dist > maxr) {
                    maxr = dist;
                }
            }
        }
 
        sort(ants.begin(), ants.end(), ant_info::cmp);
 
        int mid = 0;
 
        for (i = 0; i < ants.size(); i++)
        {
            bool left = ants[i].dir == 'L';
 
            if (left) mid++;
        }
 
        if (mid > 0) startl = ants[mid - 1].pos;
        if (mid < static_cast<int>(ants.size())) startr = ants[mid].pos;
 
        cout << "The last ant will fall down in "
             << (maxl >= maxr ? maxl : maxr)
             << " secontds - started at ";
 
        if (maxl == maxr) {
            if (startl > startr) swap(startl, startr);
            cout << startl << " and " << startr;
        } else {
            cout << (maxl > maxr ? startl : startr);
        }
        cout << "." << endl;
 
    }
 
    return 0;
 
}