JAVA 模拟 逻辑+审题仔细+表达

表示数值的字符串

class Solution {
    public boolean isNumber(String s) {
         if(s.length()==0||s==null){
             return false;
         }
         boolean numflag = false;
         boolean eflag  =false;
         boolean dotflag = false;
         s  =s.trim();
         char []ss  = s.toCharArray();
         for(int i =0;i<ss.length;i++){
             if(ss[i]>='0'&&ss[i]<='9'){
                             numflag = true;
             }
             else if(ss[i]=='.'){
                        if(dotflag||eflag){
                            return false;
                        }
                        dotflag  =true;
             }
             else if(ss[i]=='e'||ss[i]=='E'){
                if(eflag||!numflag){
                    return false;
                }
                eflag  =true;
                numflag = false;
             }
             else if(ss[i]=='+'||ss[i]=='-'){
                 if(!(i==0||ss[i-1]=='e'||ss[i-1]=='E')){
                                 return false;
                 }
             }
             else{ 
                 return false;
             }
         }
         return numflag;
    }
}

1360. 日期之间隔几天

 

请你编写一个程序来计算两个日期之间隔了多少天。

日期以字符串形式给出，格式为 YYYY-MM-DD，如示例所示。

输入：date1 = "2020-01-15", date2 = "2019-12-31"
输出：15

class Solution {
    boolean runyear(int num){
        if((num%4==0&&num%100!=0)||(num%400==0)){
                       return true;
        }
        return false;
    }
    public int[] zhuan (String s){
        String sc[]  =s.split("-");
        int a[]  =new int[sc.length];
        for(int i=0;i<sc.length;i++){
            a[i]  =Integer.parseInt(sc[i]);
        }
        return a;
    }
    public int shu(int a[]){
        int year = a[0],month=a[1],day  =a[2];
        int ans  =0;
        ans+=day-1; //天数 --> year-month-01
        int mon[]  ={0,31,28,31,30,31,30,31,31,30,31,30,31};
        //月贡献的天数
        while(month>0){
              month--;
              ans+=mon[month];//0月为0天
              if(month==2&&runyear(year))  ans+=1;
        }
        //-->: year-01-01
        ans+=365*(year-1971);
        ans+=((year-1)/4)-(1971/4);
        ans-=((year-1)/100)-(1971/100);
        ans+=((year-1)/400)-(1971/400);
        return ans;
    }
    public int daysBetweenDates(String date1, String date2) {
                int s1[]  =zhuan(date1);
                int s2[]  =zhuan(date2);
                return  Math.abs(shu(s1)-shu(s2));
    }
}