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ConcatenationBinary1680.java
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ConcatenationBinary1680.java
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import java.math.BigInteger;
import java.util.Scanner;
public class ConcatenationBinary1680{
public static int concatenatedBinary(int n) {
StringBuilder builder = new StringBuilder();
for (int i = 1; i <=n; i++) {
builder.append(Integer.toBinaryString(i));
}
return (int) binToIntger(builder.toString()) ;
}
public static long binToIntger(String str){
char []chr = str.toCharArray();
BigInteger sum=BigInteger.valueOf(0);
for (int i = 0 ; i < chr.length ; i++) {
if(chr[i]=='1'){
BigInteger pot = pow(2,chr.length-1-i);
sum = sum.add(pot);
}
}
return sum.mod(BigInteger.valueOf(1000000007)).longValue();
}
public static BigInteger pow(long base,int exp){
BigInteger sum = BigInteger.valueOf(1);
sum = sum.shiftLeft(exp);
return sum;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println(concatenatedBinary(sc.nextInt()));
}
}