1、折纸问题 package chapter_9_others; public class Problem_06_PaperFolding { public static void printAllFolds(int N) { printProcess(1, N, true); } public static void printProcess(int i, int N, boolean down) { if (i > N) { return; } printProcess(i + 1, N, true); System.out.println(down ? "down " : "up "); printProcess(i + 1, N, false); } public static void main(String[] args) { int N = 3; printAllFolds(N); } }