java小编程----括号是否匹配

错误示例：：： 当

String s = "...(...[....]....{...}...)...(.[..)..";     应输出3

package com.henu.jihe;
/*
 * String s = "...(...[....]....{...}...)...(...)..";  判断括号是否匹配 
 *	思路：遍历整个String；然后从i=0截取strFirst=s.subString(i,i+1),
 *然后在截取strEnd = s.substring(i+1);先判断strFirst是否为左括号，若是则判断在
 *strEnd中是否包含右括号，若包含则count++;
 */
public class Demo06 {
	public static void main(String[] args) {
		String s = "...(...[....]....{...}...)...(...)..";
		int count = 0;//匹配括号的数目
		for (int i = 0; i < s.length(); i++) {
			String strFirst = s.substring(i,i+1);
			String strEnd = s.substring(i+1);
			if (strFirst.equals("(") && strEnd.contains(")")) {
				count++;
			}else if (strFirst.equals("[") && strEnd.contains("]")) {
				count++;
			}else if (strFirst.equals("{") && strEnd.contains("}")) {
				count++;
			}else {
				continue;
			}
		}
		System.out.println(count);
	}
}

再一个错误示例

package com.henu.jihe;

import java.util.Arrays;
import java.util.Stack;
import java.util.Vector;

/*
 * String s = "...(...[....]....{...}...)...(...)..";  判断括号是否匹配 
 *	思路：遍历整个String；然后从i=0截取strFirst=s.subString(i,i+1),
 *然后在截取strEnd = s.substring(i+1);先判断strFirst是否为左括号，若是则判断在
 *strEnd中是否包含右括号，若包含则count++;
 */
public class Demo06_02 {
	public static void main(String[] args) {
		
		String s = "...(...[....]....{...}...)...(...)..";
		
		String[] str = s.split("\\.+");
		System.out.println(Arrays.toString(str));
		
		
		Stack<String> stack = new Stack<>();
		int count = 0;
		
		for (int i = 0; i < str.length; i++) {
			if ("(".equals(str[i])) {
				stack.push(str[i]);
				if (")".equals(str[i+1])) {
					stack.pop();
					count++;
				}
			}else if ("[".equals(str[i])) {
				stack.push(str[i]);
				if ("]".equals(str[i+1])) {
					stack.pop();
					count++;
				}
			}else if ("{".equals(str[i])) {
				stack.push(str[i]);
				if ("}".equals(str[i+1])) {
					stack.pop();
					count++;
				}
			}else {
				continue;
			}
		}
		
		System.out.println(count);
		
	}
}

 再来个错误示例：：：

package com.henu.jihe;

import java.util.Arrays;
import java.util.Stack;

public class Demo06_03 {

    public static void main(String[] args) {

        String s = "...(...[....]....{...}...)...(...)..";

        String[] str = s.split("\\.+");

        System.out.println(Arrays.toString(str));

        Stack<String> stack = new Stack<>();
        int count = 0;
        String string = "";

        for (int i = 0; i+1 < str.length; i++) {
            if ("(".equals(str[i]) || "[".equals(str[i]) || "{".equals(str[i])) {
                stack.push(str[i]);
                string = stack.peek();
            }
//            if (stack.size() != 0) {
//                string = stack.peek();
////                System.out.println(string);
//            }
            if ("(".equals(string) && ")".equals(str[i+1])) {
                stack.pop();
                count++;
            }else if ("[".equals(string) && "]".equals(str[i+1])) {
                stack.pop();
                count++;
            }else if ("{".equals(string) && "}".equals(str[i+1])) {
                stack.pop();
                count++;
            }else {
                continue;
            }
        }
        System.out.println(count);

    }

}

 重头戏：正确的：：：：

package com.henu.jihe;

import java.util.Arrays;
import java.util.Stack;

public class Demo06_03 {

    public static void main(String[] args) {

        String s = "...(...[....]....{...}...)...(...)..";

        String[] str = s.split("\\.+");

        System.out.println(Arrays.toString(str));

        Stack<String> stack = new Stack<>();
        int count = 0;
        String string = "";

        for (int i = 0; i+1 < str.length; i++) {
            if ("(".equals(str[i]) || "[".equals(str[i]) || "{".equals(str[i])) {
                stack.push(str[i]);
                string = stack.peek();
            }
//            if (stack.size() != 0) {
//                string = stack.peek();
////                System.out.println(string);
//            }
            if ("(".equals(string) && ")".equals(str[i+1])) {
                stack.pop();
                count++;
            }else if ("[".equals(string) && "]".equals(str[i+1])) {
                stack.pop();
                count++;
            }else if ("{".equals(string) && "}".equals(str[i+1])) {
                stack.pop();
                count++;
            }else {
                continue;
            }
        }
        System.out.println(count);

    }

}