update

.gitignore

@@ -3,7 +3,7 @@
 
 node_modules
 
-.class
+*.class
 
 *.exe
 *.bat

oj/bytedance-2019-interview/Calculator.java

@@ -0,0 +1,88 @@
+import java.util.Scanner;
+import java.util.Stack;
+
+public class Calculator {
+    public static void main(String[] args) {
+        try (Scanner sc = new Scanner(System.in)) {
+            String str = sc.nextLine();
+            System.out.println(calculate(str));
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static int calculate(String str) throws Exception {
+        char[] exp = str.toCharArray();
+        Stack<Character> ops = new Stack<>();
+        Stack<Integer> num = new Stack<>();
+        //   + - * / ( ) $
+        // + > > < < < > >
+        // - > > < < < > >
+        // * > > > > < > >
+        // / > > > > < > >
+        // ( < < < < < =
+        // E < < < < <   ac
+        for (int i = 0; i <= exp.length;) {
+            if (i == exp.length) {
+                if (ops.isEmpty()) break;
+                if (ops.peek() == '(') throw new Exception("Invalid exp!");
+                num.push(operate(ops.pop(), num.pop(), num.pop()));
+                continue;
+            }
+            switch (exp[i]) {
+                case '+': case '-':
+                    if (ops.isEmpty() || ops.peek() == '(') {
+                        ops.push(exp[i]);
+                        i++;
+                    } else {
+                        num.push(operate(ops.pop(), num.pop(), num.pop()));
+                    }
+                    break;
+                case '*': case '/':
+                    if (ops.isEmpty() || ops.peek() == '(' || ops.peek() == '+' || ops.peek() == '-') {
+                        ops.push(exp[i]);
+                        i++;
+                    } else {
+                        num.push(operate(ops.pop(), num.pop(), num.pop()));
+                    }
+                    break;
+                case '(':
+                    ops.push('(');
+                    i++;
+                    break;
+                case ')':
+                    if (ops.isEmpty()) throw new Exception("Invalid exp!");
+                    if (ops.peek() == '(') {
+                        ops.pop();
+                        i++;
+                    } else {
+                        num.push(operate(ops.pop(), num.pop(), num.pop()));
+                    }
+                    break;
+                default:
+                    int j;
+                    for (j = i + 1; j < exp.length && '0' <= exp[j] && exp[j] <= '9'; j++);
+                    int n = Integer.parseInt(str.substring(i, j));
+                    num.push(n);
+                    i = j;
+            }
+        }
+        if (num.size() != 1) throw new Exception("Invalid exp!");
+        return num.peek();
+    }
+
+    private static int operate(char op, int n2, int n1) throws Exception {
+        switch (op) {
+            case '+':
+                return n1 + n2;
+            case '-':
+                return n1 - n2;
+            case '*':
+                return n1 * n2;
+            case '/':
+                if (n2 == 0) throw new Exception("Divided by 0!");
+                return n1 / n2;
+        }
+        return 0;
+    }
+}

oj/bytedance-2019-interview/calculator.go

@@ -1,17 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"strconv"
-	"errors"
-)
-
-func calculate(str string) (float64, error) {
-	
-}
-
-func nextInt()
-
-func main() {
-	
-}