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HashMap<Character,Integer> map = new HashMap<Character,Integer>(){{
        put('+',1);
        put('-',1);
        put('*',2);
    }};

    void calc(LinkedList<Integer> nums,LinkedList<Character> operators){
        if(nums.isEmpty()||nums.size()<2){
            return;
        }

        if(operators.isEmpty()){
            return;
        }

        int b = nums.pollLast();
        int a = nums.pollLast();
        char operator = operators.pollLast();

        int res = 0;

        if(operator=='+'){
            res = a+b;
        }else if(operator=='-'){
            res = a-b;
        }else if(operator=='*'){
            res = a*b;
        }
        nums.addLast(res);
    }
    public int solve(String s) {
        s = s.replaceAll(" ", "");

        char[] str = s.toCharArray();
        int n = s.length();


        LinkedList<Integer> nums = new LinkedList<>();
        LinkedList<Character> operators = new LinkedList<>();
        nums.addLast(0);

        for(int i=0;i<n;i++){
            char c = str[i];

            if(c=='('){
                operators.addLast(c);
            }else if(c==')'){
                while(!operators.isEmpty()){
                    if(operators.peekLast()!='('){
                        calc(nums,operators);
                    }else{
                        operators.pollLast();
                        break;
                    }
                }
            }else{
                if(Character.isDigit(c)){
                    int base = 0;
                    int j=i;
                    while(j<n&&Character.isDigit(str[j])){
                        base=base*10+(str[j++]-'0');
                    }
                    nums.addLast(base);
                    i=j-1;
                }else{
                    if(i>0&&(str[i-1]=='('||str[i-1]=='+'||str[i-1]=='-')){
                        nums.addLast(0);
                    }

                    while(!operators.isEmpty()&&operators.peekLast()!='('){
                        char prev = operators.peekLast();
                        if(map.get(prev)>=map.get(c)){
                            calc(nums,operators);
                        }else{
                            break;
                        }
                    }
                    operators.addLast(c);
                }
            }
        }

        while(!operators.isEmpty()&&operators.peekLast()!='('){
            calc(nums,operators);
        }
        return nums.peekLast();
        

    }