Package g0201_0300.s0227_basic_calculator_ii

Class Solution

java.lang.Object
g0201_0300.s0227_basic_calculator_ii.Solution
public class Solution extends java.lang.Object
227 - Basic Calculator II.

Medium

Given a string s which represents an expression, evaluate this expression and return its value.

The integer division should truncate toward zero.

You may assume that the given expression is always valid. All intermediate results will be in the range of [-231, 231 - 1].

Note: You are not allowed to use any built-in function which evaluates strings as mathematical expressions, such as eval().

Example 1:

Input: s = “3+2*2”

Output: 7

Example 2:

Input: s = " 3/2 "

Output: 1

Example 3:

Input: s = " 3+5 / 2 "

Output: 5

Constraints:

  • 1 <= s.length <= 3 * 105
  • s consists of integers and operators ('+', '-', '*', '/') separated by some number of spaces.
  • s represents a valid expression.
  • All the integers in the expression are non-negative integers in the range [0, 231 - 1].
  • The answer is guaranteed to fit in a 32-bit integer.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    calculate(java.lang.String s)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • calculate

      public int calculate(java.lang.String s)