java常见算法

1.冒泡排序

public int[] bubbleSort(int arr){
	int temp;
	boolean isOk;
	for(int i = 0; i < arr.length; i++){
		isOk = true;
		for(int j = 0; j < arr.length - i - 1; j++){
		   if(arr[j] > arr[j + 1]){
			   temp = arr[j];
			   arr[j] = arr[j + 1];
			   arr[j + 1] = temp;
			   isOk = false;
		   }
		}
		if(isOk){
			break;
		}
	}
	return arr;
}

2.阶乘

public int calculatorJ(int j){
	return j == 1 ? 1 : j * calculatorJ(j - 1);
}

3.最大公约数

public int divisor(int m, int n){
	if(m % n == 0)
		return n;
	else
	   return divisor(n, m % n);
}

4.最小公倍数

public int getGBS(int n1, int n2){
	int gbs = n1 * n2 / divisor(n1,n2);
	return gbs;
}

5.验证字符串是否符合由(),[],{}组成的不交叉表达式

public boolean metchBreaker(String s){
	List<Character> list = new LinkedList<Character>();
	char c;
	try{
		for(int i = 0; i < s.length(); i++){
			c = s.charAt(i);
			switch (c)
			{
				case '{':
				case '[':
				case '(':
					list.add(c);
					break;
				case '}':
					if('{' == list.get(list.size() - 1)){
						list.remove(list.size() - 1);
					}else{
						return false;
					}
					break;
				case ']':
					if('[' == list.get(list.size() - 1)){
						list.remove(list.size() - 1);
					}else{
						return false;
					}
					break;
				case ')':
					if('(' == list.get(list.size() - 1)){
						list.remove(list.size() - 1);
					}else{
						return false;
					}
					break;
			}
		}
	}catch (Exception e) {
		return false;
	}
	if(list.isEmpty())
		return true;
	else
		return false;

}