ICPC 模擬予選 A

A.cpp

#include <iostream>
#include <map>
#include <string> 
#include <vector>
#include <cstdio>

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

using namespace std;

int main(int argc, const char * argv[]){
	int N;
	while(cin >> N, N){
		int cnt = 0;
		bool nextUp = true;
		int numUp = 0; //上に登ってる足の数
		string step;
		for (int i = 0; i < N; ++i){
			cin >> step;
			if (step == "ru" || step == "lu"){
				numUp ++;
			} else {
				numUp --;
			}

			if ((nextUp && numUp == 2) || (!nextUp && numUp == 0)){
				nextUp = !nextUp;
				cnt ++;
			}
		}
		cout << cnt << endl;
	}
	return 0;
}