题解 | #四则运算#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
    // Write your code here
    while ((line = await readline())) {
        let st = line
            .replace("[", "(")
            .replace("]", ")")
            .replace("{", "(")
            .replace("}", ")");
        // console.log(st);
        function func(i) {
            let nums = [];

            let flag = null;
            while (i < st.length) {
                let num = 0;
                if (st[i] == "(") {
                    [i, num] = func(i + 1);
                }
                while (i < st.length && /[0-9]/.test(st[i])) {
                    num = num * 10 + Number(st[i]);
                    i += 1;
                }
                if (nums.length == 0) {
                    nums.push(num);
                }
                if (flag == "+") {
                    nums.push(num);
                } else if (flag == "-") {
                    nums.push(-num);
                } else if (flag == "*") {
                    nums.push(nums.pop() * num);
                } else if (flag == "/") {
                    nums.push(nums.pop() / num);
                }
                if (i < st.length && /[\+\-\*\/]/.test(st[i])) {
                    flag = st[i];
                    i++;
                }
                if (st[i] == ")") {
                    return [i + 1, sum(nums)];
                }
            }
            return [i, sum(nums)];
        }
        function sum(arr) {
            var s = 0;
            for (var i = arr.length - 1; i >= 0; i--) {
                s += arr[i];
            }
            return s;
        }
        console.log(func(0)[1]);
    }
})();