小编ash*_*eil的帖子

我正在研究什么本质上是调车码算法，但是将中缀移动到前缀而不是 RPN 我试图保留括号，并且我有一段时间的恶魔。目前我的代码是

        String s = inFixList.get(i);
        Stack<Character> opStack = new Stack<Character>();
        Stack<Character> solutionStack = new Stack<Character>();
        String solution = "";

        for(char c : s.toCharArray())
        {
            if(Character.isLetter(c)||Character.isDigit(c))
            {
                solutionStack.push(c);
            }
            else if(c == '(')
            {
                opStack.push(c);
                solutionStack.push(')');
            }
            else if(c == ')')
            {                   
                while(opStack.peek() != '(')
                {
                    solutionStack.push(opStack.pop());
                    solutionStack.push('(');
                }
                opStack.pop();
            }
            else if (!Character.isSpaceChar(c))
            {
                if(opStack.isEmpty())
                {
                    opStack.push(c);
                }                       
                else if(opStack.peek()!='(' &&(OPERATORS.indexOf(c) < OPERATORS.indexOf(opStack.peek())))
                {
                    opStack.push(c);
                }
                else if(!opStack.isEmpty()&&(opStack.peek()!='('))
                {
                    solutionStack.push(opStack.pop());
                    solutionStack.push('(');
                    opStack.push(c);

                }
                else
                {
                    opStack.push(c);
                }

            } …