230912 스킬트리

public int solution(String skill, String[] skillTrees) {
	int answer = 0;
	for (String skillTree : skillTrees) {
		if (isSkillValid(skill, skillTree)) {
			answer++;
		}
	}
	return answer;
}

private boolean isSkillValid(String skill, String skillTree) {
	StringBuilder filteredSkillTree = new StringBuilder();
	for (char c : skillTree.toCharArray()) {
		if (skill.contains(Character.toString(c))) {
			filteredSkillTree.append(c);
		}
	}
	return skill.startsWith(filteredSkillTree.toString());
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/49993