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解决Next Greater Number问题

• 使用取模来实现循环
  

  问题：

  1.

  

  2.天气温度

  

  3.循环数组

  

4.计算器相关

function calculate(s){
    let list = s.split('');
  function helper(list){
      let stack=[],num=0,sign='+';
    while(list.length){
        const c = list.pop();
      if(!isNaN(c)){
          num = num*10+(c-'0');
      }
      if(c==='('){
          num = helper(list)
      }
      if(c!===' '&&(c==='+' || c==='-' || c==='*' || c==='/') || !list.length){
          if(sign==='+'){
            stack.push(num)
        }else if(sign==='-'){
            stack.push(-num)
        }else if(sign==='*'){
            const top = stack.pop();
          const temp = top*num;
          stack.push(temp)
        }else if(sign==='/'){
            const top = stack.pop();
          const temp = Math.floor(top/num);
          stack.push(temp)
        }
        sign = c;
        num=0;
      }
      if(c===')'){
          break;
      }
    }
    return stack.reduce((pre,next)=>pre+next,0);
  }
  return helper(list);
}