Hdoj (HDU) 2502-month number (binary)

Problem Description
When the cold month is still reading freshman year, he in a martial arts cheats (according to later research, is the Computer Foundation, Kuanghan-ing), found the magic of binary numbers.
If a positive integer m is represented as a binary, its number of BITS is n (without leading 0), and the cold month is called an n binary number. Of all n binary numbers, the total number of 1 is called the number of months corresponding to N.
For example, the total number of 32 binary is 4, 4 (100), 5 (101), 6 (110), 7 (111), and 1 of them are 1+2+2+3=8, so 3 corresponds to 8 of the month.

Input
Give you an integer t that represents the number of groups of input data, followed by a T-line, each containing a positive integer n (1<=n<=20).

Output
For each n, the number of months that corresponds to the output n in a row.

Sample Input
3
1
2
3

Sample Output
1
3
8

This topic. Using Java to calculate a timeout of 0.0

N-bit binary number a total number of x=2^ (n-1), and then a few examples can be seen:
For example:
Enter 4, then there are so many 4-bit binary numbers:
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
The first column has x 1, each column has X/2 1, then a total of s=x+ (n-1) *X/2 1

JAVAAC:

Import Java.util.Scanner; Public classmain{ Public Static void Main(string[] args) {Scanner sc=NewScanner (System.inch);intT =sc.nextint (); while(t-->0){intn =sc.nextint ();intCont =0;intx = (int) Math.pow (2, N-1);//int x = (int) Math.pow (2, N)-(int) Math.pow (2, n-1);//Samecont+=x* (n1)/2; System. out. println (CONT+X); }    }}

C Analog Output:
(This will time out in Java)

#include <iostream>#include <stdio.h>#include <math.h>using namespace STD;intMain () {intt;scanf("%d", &t); while(t-->0){intn;intCont =0;intXscanf("%d", &n); for(intI=POW(2, N-1); i<=POW(2, N)-1; i++) {x=i; while(x>0)                {if((%2)==1) cont++; X/=2; }            }printf("%d\n", cont); }    }

Hdoj (HDU) 2502-month number (binary)