十六進位制轉十進位制
package LQB;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class Basic11 {
public static void main(String [] args){
Scanner sc = new Scanner(System.in);
String n = sc.next();
Map<Character,Integer> map = new HashMap<Character, Integer>();
for(int i = 0;i<10;i++){
map.put((char)(48+i),i);
}
for(int i=0;i<7;i++){
map.put((char)(65+i), 10+i);
}
long [] arr = {1,16,256,4096,65536,1048576,16777216,268435456};
char [] arr2 = n.toCharArray();
char [] arr3 = new char[arr2.length];
for(int i=0;i<arr2.length;i++){
arr3[i]=arr2[arr2.length-i-1];
}
long sum=0;
for(int i =arr3.length-1;i>=0;i--){
sum+=(arr[i]*map.get(arr3[i]));
}
System.out.println(sum);
}
}