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Vp.java
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61 lines (56 loc) · 1.67 KB
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package ValidParentheses020;
import java.util.Stack;
/**
* Created by Administrator on 2017/8/30.
*/
public class Vp {
//方法1。把括号左边({[压入堆栈，与下一个对比，相同则出栈
/*public boolean isValidParentheses(String s){
Stack<Character> stack=new Stack<Character>();
for(Character c:s.toCharArray()){
if("({[".contains(String.valueOf(c))){
stack.push(c);
}else{
if(!stack.isEmpty()&&is_valid(stack.peek(),c)){
stack.pop();
}else{
return false;
}
}
}
return stack.isEmpty();
}
private boolean is_valid(char c1,char c2){
return (c1=='('&&c2==')')||(c1=='{'&&c2=='}')||(c1=='['&&c2==']');
}*/
//方法2
public boolean isValidParentheses(String s){
Stack<Character> stack=new Stack<Character>();
for(char c:s.toCharArray()){
if(c=='('||c=='{'||c=='['){
stack.push(c);
}
if(c==')'){
if(stack.isEmpty()||stack.pop()!='('){
return false;
}
}
if(c==']'){
if(stack.isEmpty()||stack.pop()!='['){
return false;
}
}
if(c=='}'){
if(stack.isEmpty()||stack.pop()!='{'){
return false;
}
}
}
return stack.isEmpty();
}
public static void main(String[] args){
String s="([)]";
boolean res=new Vp().isValidParentheses(s);
System.out.print(res);
}
}