ants.cpp

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
 
#include <iostream>
#include <algorithm>
 
#include <vector>
#include <string>
#include <map>
#include <queue>
#include <deque>
#include <stack>
#include <set>
 
//~ using namespace std;
 
typedef long double num;
typedef long long int lint;
typedef struct { int x, y; } intpoint;
typedef struct { num x, y; } numpoint;
typedef struct { lint x, y; } lintpoint;
 
#define EPS (1e-7L)
#define PI (4.0L * atanl(1.0L))
 
#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))
#define abs(a) ((a) < 0 ? -(a) : (a))
 
int main(int argc, char *argv[]) {
	while (true) {
		int ants, len;
 
		bool existL = false, existR = false, collision;
 
		if (2 != scanf("%u %u\n", &len, &ants))
			break;
		int maxL = 0, minR = len, mindist = len;
		std::vector<int> antssssss;
 
 
 
		bool hasR = false, hasL = false;
		int startR = INT_MAX, startL = 0;
 
		for (int ant = 0; ant < ants; ant++) {
			int start;
			char dir;
 
			scanf("%u %c\n", &start, &dir);
 
			if (dir == 'L' && startL <= start) {
				existL = true;
				maxL = max(maxL, start);
 
				hasL = true;
				startL = start;
			} else if (dir == 'R' && start <= startR) {
				existR = true;
				minR = min(minR, start);
 
				hasR = true;
				startR = start;
			}
			int aux = len%2 ? min(abs(len/2 - start), abs(len/2 + 1 - start)) : abs((len >>1) - start);
				if (aux < mindist) 
				{
					antssssss.clear();
					antssssss.push_back(start);
					mindist = aux;
				}
				else
					if(aux == mindist)
						antssssss.push_back(start);
 
		}
 
 
 
		int L = startL, R = len - startR;
		if (existL && existR) {
			if (minR < maxL) {
				if(antssssss.size() == 2)
					printf("The last ant will fall down in %d seconds - started at %d and %d.\n", max(L, R), antssssss[0], antssssss[1]);
				else
					printf("The last ant will fall down in %d seconds - started at %d.\n", max(L, R), antssssss[0]);
			}
		} else if (existR) {
			printf("The last ant will fall down in %d seconds - started at %d.\n", R, startR);
		} else if (existL) {
			printf("The last ant will fall down in %d seconds - started at %d.\n", L, startL);
		} else {
			// not gonna happen
		}
	}
 
	return 0;
}