🐣 문제

링크 : https://www.acmicpc.net/problem/2806

🐥 코드

/*
문제 : DNA 발견
링크 : https://www.acmicpc.net/problem/2806
*/

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int A[1000000];
int B[1000000];

int main() {
	int n;
	cin >> n;

	vector<int> v;
	for(int i = 0; i < n; i++){
		char c;
		cin >> c;

		v.push_back(c);
	}

	if(v[0] == 'A'){
		A[0] = 0;
		B[0] = 1;
	}

	else{
		A[0] = 1;
		B[0] = 0;
	}

	for(int i = 1; i < n; i++){
		if(v[i] == 'A'){
			A[i] = min(A[i-1], B[i-1] + 1);
			B[i] = min(A[i-1] + 1, B[i-1] + 1);
		}
		else{
			A[i] = min(A[i-1] + 1, B[i-1] + 1);
			B[i] = min(A[i-1] + 1, B[i-1]);
		}
	}

	cout << A[n-1];
}