京东java 第三题括号匹配，只通过10%为什么

package Main;

import java.util.LinkedList;
import java.util.Scanner;

public class Main{
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
while(sc.hasNext()) {
int n = sc.nextInt();
String str[] = new String[n];
for(int i=0;i<n;i++) {
str[i] = sc.next();
}

for(int i=0;i<n;i++) {
if(canPassBySwapOnce(str[i])) {
System.out.println("Yes");
}else {
System.out.println("No");
}
}
}
}

static boolean canPassBySwapOnce(String str) {
LinkedList stack = new LinkedList();
for (Object object : stack) {
System.out.println(object);
}
if(str.length()%2 == 1) {
return false;
}else {
for(int i=0;i<str.length();i++) {
if(stack.size() !=0 && (char)stack.peek() == '(' && str.charAt(i) == ')') {
stack.pop();
}else {
stack.push(str.charAt(i));
}
}
if(stack.size() == 2) {
return true;
}else {
return false;
}
}
}
}

#实习#