弹簧人算法

import java.util.Scanner;

//弹簧人从500米落下来时，回弹高度会衰竭一半，第n次落地时经过的距离是多少米
public class Main{

public static float getToal(int times) {

float result = 0, currVal = 500;

for(int i = 0; i < times; i++) {

result += currVal;

currVal = currVal/2;
}

result = result * 2 - 500;

if (String.valueOf(result).indexOf('.') < 0) {
String tmp = String.valueOf(result) + ".0";
return Float.valueOf(tmp);

}else {
return result;
}
}

public static void main(String[] args) {

Scanner input = new Scanner(System.in);

int times = 0;

try {
times = input.nextInt();
} catch (Exception e) {

}


if (times > 0) {
System.out.println(getToal(times));
}else {
System.out.println(0);
}


}
}