package basic; /** * Created by zxc on 2018/3/23. */ public class ArithmeticOne { public static void main(String[] args) { //int num = countWord("Please follow the Wechat public number"); //isUgly(30); //System.out.println("关注公众号：Java3y--->" + "Please follow the Wechat public number"); //Factorial(3); Factorial(7); } /** * 判断一个数字是不是ugly number（分解出来的质因数只有2、3、5这3个数字） * * @param num */ public static void isUgly(int num) { if (num <= 0) { System.out.println("不是"); } else { while (num % 2 == 0) { num = num / 2; } while (num % 3 == 0) { num = num / 3; } while (num % 5 == 0) { num = num / 5; } if (num == 1) { System.out.println("是"); } else { System.out.println("是"); } } } /** * 判断是否是2的某次方 */ public static void isPowerOfTwo() { int num = 8; /* if (num == 0) { System.out.println("不是"); } while (num % 2 == 0) { num = num / 2; } if (num == 1) { System.out.println("是"); } else { System.out.println("不是"); } */ if (num <= 0) { System.out.println("不是"); } else if (num == 1) { System.out.println("是"); } else { if ((num & (num - 1)) == 0) { System.out.println("是"); } else { System.out.println("不是"); } } } /** * 给定两个字符串s和t，判断这两个字符串中的字母是不是完全一样（顺序可以不一样） */ public static void isAnagram() { //分别存储字符串的字符 char[] array1 = new char[26]; char[] array2 = new char[26]; String s1 = "pleasefollowthewechatpublicnumber"; String s2 = "pleowcnumberthewechatpubliasefoll"; for (int i = 0; i < s1.length(); i++) { char value = s1.charAt(i); // 算出要存储的位置 int index = value - 'a'; array1[index]++; } for (int i = 0; i < s2.length(); i++) { char value = s2.charAt(i); // 算出要存储的位置 int index = value - 'a'; array2[index]++; } for (int i = 0; i < 26; i++) { if (array1[i] != array2[i]) { System.out.println("不相同"); return; } } System.out.println("相同"); } /** * 输入一段字符，计算出里面单词的个数 * * @param str 一段文字 */ public static int countWord(String str) { // 0 表示空格状态，1 表示非空格状态 int flag = 0; // 单词次数 int num = 0; for (int i = 0; i < str.length(); i++) { if (String.valueOf(str.charAt(i)).equals(" ")) { flag = 0; } else if (flag == 0) { num++; flag = 1; } } return num; } /** * 猴子吃桃问题 * * @param x 天数 */ public static int monkeyQue(int x) { /* //循环方式： int x = 1; for (int i = 1; i <= 9; i++) { x = (x + 1) * 2; } */ if (x <= 0) { return 0; } else if (x == 1) { return 1; } else { return 2 * monkeyQue(x - 1) + 2; } } /** * 打印杨辉三角形 */ public static void PascalTriangle() { //打印十行的杨辉三角形 int[][] arrays = new int[10][]; //行数 for (int i = 0; i < arrays.length; i++) { //初始化第二层的大小 arrays[i] = new int[i + 1]; //列数 for (int j = 0; j <= i; j++) { //是第一列并且行数等于列数，那么通通为1 if (i == 0 || j == 0 || j == i) { arrays[i][j] = 1; } else { //当前值等于头上的值+头上左边的值 arrays[i][j] = arrays[i - 1][j] + arrays[i - 1][j - 1]; } } } System.out.println("公众号：Java3y" + "-------------------------------"); for (int[] array : arrays) { for (int value : array) { System.out.print(value + "\t"); } System.out.println(); } System.out.println("公众号：Java3y" + "-------------------------------"); } /** * 数组对角线之和 */ public static void arraySum() { int[][] arrays = { {23, 106, 8, 234}, {25, 9, 73, 19}, {56, 25, 67, 137}, {33, 22, 11, 44}, }; //和 int sum = 0; for (int i = 0; i < arrays.length; i++) { for (int j = 0; j < arrays[i].length; j++) { if (i == j) { sum = sum + arrays[i][j]; } } } System.out.println("公众号：Java3y" + sum); } /** * 1-n的阶乘之和 */ public static void Factorial(int n) { //总和 double sum = 0; //阶乘值，初始化为1 double factorial = 1; for (int i = 1; i <= n; i++) { factorial = factorial * i; sum = (int) (sum + factorial); } System.out.println("公众号：Java3y" + " " + sum); } /** * 求出二维数组每列的最小值 */ public static void minArray() { //二维数组 int[][] arrays = { {23, 106, 8, 234}, {25, 9, 73, 19}, {56, 25, 67, 137} }; //获取列数 int maxColLength = arrays[0].length; //使用一个数组来装载每列最小的值 int[] minArray = new int[maxColLength]; //控制列数 for (int i = 0; i < maxColLength; i++) { //假设每列的第一个元素是最小的 int min = arrays[0][i]; //控制行数 for (int j = 1; j < arrays.length; j++) { //找到最小值 if (arrays[j][i] < min) { min = arrays[j][i]; } } //赋值给装载每列最小的值的数组 minArray[i] = min; } System.out.println("公众号：Java3y" + " " + minArray); } /** * 求"1！+4！(2的平方)+9！(3的平方)+...+n的值 */ public static void calculate() { double sum = 0; for (int i = 1; i <= 3; i++) { //得到平方数 int square = i * i; //阶乘值，从1开始 double factorial = 1; //求阶乘 for (int j = 1; j <= square; j++) { factorial = factorial * j; } sum = sum + factorial; } System.out.println("公众号：Java3y" + " " + sum); } }