题解 | #查找输入整数二进制中1的个数#

public class Main {
    public static void main(String[] args) {
       Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int b = n-1;
        int s = (1+b)*b/2;    // n-1行元素总数
         int ss = 2*s+1;      // n行起始数字
        StringBuilder sb = new StringBuilder();
        for (int i = ss; n>0; i=i+2,n--) {
            sb.append(i).append('+');
        }
        System.out.println(sb.toString().substring(0,sb.lastIndexOf("+")));
  
    }
}