ants.cpp

#include <cstdio>
 
using namespace std;
 
 
int main(void) {
	int count, length;
 
	while(scanf("%d%d\n", &length, &count) == 2) {
		int leftmost = -1, rightmost = -1;
		bool ants[100000];
		for(int i = 0; i < 100000; ++i) ants[i] = false;
 
		int pos;
		char dir;
 
		int toLeft = 0;
 
		for(int a = 0; a < count; ++a) {
			scanf("%d %c\n", &pos, &dir);
			ants[pos] = true;
			if(dir == 'R' && (leftmost == -1 || pos < leftmost)) {
				leftmost = pos;
			}
			else if(dir == 'L' && (rightmost == -1 || pos > rightmost)) {
				rightmost = pos;
			}
 
			if(dir == 'L') ++toLeft;
		}
 
		int maxTime = 0;
		if(leftmost != -1) maxTime = length - leftmost;
		if(rightmost != -1 && rightmost > maxTime) maxTime = rightmost;
 
		printf("The last ant will fall down in %d seconds - started at ", maxTime);
 
		if(rightmost == length - leftmost) {
			int passed = 0;
			for(int a = 0; a < length; ++a) {
				if(!ants[a]) continue;
				++passed;
 
				if(passed == toLeft) {
					printf("%d and ", a);
				}
				else if(passed == toLeft + 1) {
					printf("%d", a);
					break;
				}
			}
		}
		else if(maxTime == length - leftmost) {
			int passed = 0;
			for(int a = 0; a < length; ++a) {
				if(!ants[a]) continue;
				if(++passed == toLeft + 1) {
					printf("%d", a);
					break;
				}
			}
		}
		else {
			int passed = 0;
			for(int a = 0; a < length; ++a) {
				if(!ants[a]) continue;
				if(++passed == toLeft) {
					printf("%d", a);
					break;
				}
			}
		}
 
		printf(".\n");
	}
 
	return 0;
}