package algorithm.basic; import org.omg.PortableInterceptor.INACTIVE; import java.io.Console; /** * @Created by mood321 * @Date 2019/10/8 0008 * @Description TODO */ public class Test { public static boolean isSum(int[] arr ,int sum,int cur,int i){ if(i==arr.length){ return sum==cur; } return isSum(arr,sum,cur,i+1)||isSum(arr,sum,arr[i]+cur,i+1); } /* public static void main(String[] args) { *//* int[] ints = {2, 3, 4, 5, 7}; System.out.println(isSum(ints,11,0,0));*//* printNum(1,3,9); }*/ /** 9*1=9 8*1=8 7*1=7 9*2=18 8*2=16 7*2=14 9*3=27 8*3=24 7*3=21 9*4=36 8*4=32 7*4=28 9*5=45 8*5=40 7*5=35 9*6=54 8*6=48 7*6=42 9*7=63 8*7=56 7*7=49 9*8=72 8*8=64 7*8=56 9*9=81 8*9=72 7*9=63 6*1=6 5*1=5 4*1=4 6*2=12 5*2=10 4*2=8 6*3=18 5*3=15 4*3=12 6*4=24 5*4=20 4*4=16 6*5=30 5*5=25 4*5=20 6*6=36 5*6=30 4*6=24 6*7=42 5*7=35 4*7=28 6*8=48 5*8=40 4*8=32 6*9=54 5*9=45 4*9=36 3*1=3 2*1=2 1*1=1 3*2=6 2*2=4 1*2=2 3*3=9 2*3=6 1*3=3 3*4=12 2*4=8 1*4=4 3*5=15 2*5=10 1*5=5 3*6=18 2*6=12 1*6=6 3*7=21 2*7=14 1*7=7 3*8=24 2*8=16 1*8=8 3*9=27 2*9=18 1*9=9 */ public static void main(String[] args) { /*for (int count=9;count>0;count--){ if(count%3==0){ echo(count); } }*/ echo1(); /* System.out.println(3|2); System.out.println(4&3);*/ } private static synchronized void echo1() { for (int s=9;s>0;){ er(s); s-=3; } } private static void er(int s) { for (int e=1;e<=9;e++){ System.out.print(s + "*" + e + "="+s*e+ " "); System.out.print(s-1 + "*" + e + "="+(s-1*e)+ " "); System.out.print(s-2 + "*" + e + "="+(s-1*e)+ " "); System.out.println(); } System.out.println(); } static void echo(int row) { int len=1,a=row; for (int i = 9; i >= 1; i--) { for (int j = 1; j <= 3; j++) { System.out.print(row + "*" + len + "="+row*len+ " "); row--; } len++; row = a; System.out.print("\n"); } } }