ants.cpp

#include <vector>
#include <algorithm>
#include <cstdio>
using namespace std;
 
int main() {
	int l, a;
	while(scanf("%d %d", &l, &a) == 2) {
		vector<int> pos(a);
		vector<int> left;
		vector<int> right;
		for (int i = 0; i < a; ++i) {
			char c;
			scanf("%d %c", &pos[i], &c);
			if (c == 'L')
				left.push_back(pos[i]);
			else
				right.push_back(l - pos[i]);
		}
		sort(pos.begin(), pos.end());
		sort(left.begin(), left.end());
		sort(right.begin(), right.end());
		int i1 = left.size() - 1;
		int i2 = i1 + 1;
		if (i1 >= 0 && i2 < a && left.back() == right.back()) {
			printf("The last ant will fall down in %d seconds - started at %d and %d.\n", left.back(), pos[i1], pos[i2]);
		} else {
			int tlast, xlast;
			if (i1 < 0 || (i2 < a && left.back() < right.back())) {
				tlast = right.back();
				xlast = pos[i2];
			} else {
				tlast = left.back();
				xlast = pos[i1];
			}
			printf("The last ant will fall down in %d seconds - started at %d.\n", tlast, xlast);
		}
 
	}
}