Java栈的应用之括号匹配算法实例分析

class Solution {
  public boolean isValid(String s) {
    Stack<Character> stack=new Stack<Character>();
    for (int i=0;i<s.length();i++){
      char c=s.charAt(i);
      if(c=='('||c=='['||c=='{'){
        stack.push(c);
      }else {
        if(stack.isEmpty())
          return false;

        char topChar=stack.pop();
        if(c==')'&&topChar!='(')
          return false;
        if (c==']'&&topChar!='[')
          return false;

        if(c=='}'&&topChar!='{')
          return false;
      }
    }
    return stack.isEmpty();
  }
}