2694:逆波蘭表示式
阿新 • • 發佈:2019-02-20
總時間限制:
java.util.LinkedList;
import java.util.Scanner;
public classMain{
public static void main(String[] args) {
Scannerinput = new Scanner(System.in);
String [] str =input.nextLine().split(" ");
LinkedListlink =new LinkedList();
for(Stringo : str){
link.add(o);
}
Stringa;
double b,c,d;
for(int i=link.size()-1 ;link.size()>1;i--){
a=(String)link.get(i);
if(a.equals("+")){
b=Double.parseDouble((String)link.get(i+1));
c=Double.parseDouble((String)link.get(i+2));
d=b+c;
link.add(i,String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
if(a.equals("-")){
b=Double.parseDouble((String)link. get(i+1));
c=Double.parseDouble((String)link.get(i+2));
d=Math.abs(b-c);//關鍵的一步
link.add(i,String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
if(a.equals("*")){
b=Double.parseDouble((String)link.get(i+1));
c=Double.parseDouble((String)link.get(i+2));
d=b*c;
link.add(i, String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
if(a.equals("/")){
b=Double.parseDouble((String)link.get(i+1));
c=Double.parseDouble((String)link.get(i+2));
d=b/c;
link.add(i,String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
}
System.out.printf("%.6f",Double.parseDouble((String) link.getLast()));
System.out.println();
}
}
- 1000ms
- 記憶體限制:
- 65536kB
- 描述
- 逆波蘭表示式是一種把運算子前置的算術表示式,例如普通的表示式2 + 3的逆波蘭表示法為+ 2 3。逆波蘭表示式的優點是運算子之間不必有優先順序關係,也不必用括號改變運算次序,例如(2 + 3) * 4的逆波蘭表示法為* + 2 3 4。本題求解逆波蘭表示式的值,其中運算子包括+ - * /四個。
- 輸入
- 輸入為一行,其中運算子和運算數之間都用空格分隔,運算數是浮點數。
- 輸出
- 輸出為一行,表示式的值。
可直接用printf("%f\n", v)輸出表達式的值v。 - 樣例輸入
-
* + 11.0 12.0 + 24.0 35.0
- 樣例輸出
-
1357.000000
import
import java.util.Scanner;
public classMain{
public static void main(String[] args) {
Scannerinput = new Scanner(System.in);
String [] str =input.nextLine().split(" ");
LinkedListlink =new LinkedList();
for(Stringo : str){
link.add(o);
}
Stringa;
double b,c,d;
for(int i=link.size()-1
a=(String)link.get(i);
if(a.equals("+")){
b=Double.parseDouble((String)link.get(i+1));
c=Double.parseDouble((String)link.get(i+2));
d=b+c;
link.add(i,String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
if(a.equals("-")){
b=Double.parseDouble((String)link.
c=Double.parseDouble((String)link.get(i+2));
d=Math.abs(b-c);//關鍵的一步
link.add(i,String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
if(a.equals("*")){
b=Double.parseDouble((String)link.get(i+1));
c=Double.parseDouble((String)link.get(i+2));
d=b*c;
link.add(i, String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
if(a.equals("/")){
b=Double.parseDouble((String)link.get(i+1));
c=Double.parseDouble((String)link.get(i+2));
d=b/c;
link.add(i,String.valueOf(d));
link.remove(i+1);
link.remove(i+1);
link.remove(i+1);
}
}
System.out.printf("%.6f",Double.parseDouble((String) link.getLast()));
System.out.println();
}
}