LeetCode——20. 有效的括号

题目描述：

注：本分类博客中的所有代码可以直接拷贝到eclipise

代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;

class Solution {

	public boolean isValid(String s) {

		Stack<Character> stack = new Stack<>();
		char[] array = s.toCharArray();
		for (int i = 0; i < array.length; i++) {
			// 栈空就入栈
			if (stack.isEmpty()) {
				stack.push(array[i]);
				// 判断是否匹配，匹配就弹出
			} else if (isMarch(stack.peek(), array[i])) {
				stack.pop();
			} else {
				stack.push(array[i]);
			}
		}
		// 栈空说明匹配成功
		return stack.size() == 0;

	}

	// 匹配栈顶与数组括号是否匹配
	public boolean isMarch(char a, char b) {

		if ((a == '(' && b == ')') || (a == '[' && b == ']') || (a == '{' && b == '}')) {
			return true;
		}
		return false;

	}
}

public class MainClass {

	public static String booleanToString(boolean input) {
		return input ? "True" : "False";
	}

	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String line;
		while ((line = in.readLine()) != null) {

			boolean ret = new Solution().isValid(line);

			String out = booleanToString(ret);

			System.out.print(out);
		}
	}
}