Android interview Java Algorithm question [Android evolution 4]

Summarize the algorithm questions previously interviewed by the company. There are roughly the following types: one for loop, two for loops, sorting, comparison size, recursion, and so on. I hope it will be helpful to people looking for a job. I haven't figured out some of my questions yet! After I understand it, I will post it for sharing!

1. To write a method, enter a string abcdefg and output gfedcba in reverse order:

Package com.cn. test; public class stringdaoxu {Public String formatstring (string s) {// use the for reverse loop, and use the char type method to implement for (INT I = S. length ()-1; I> = 0; I --) {system. out. print (S. charat (I);} return s;}/*** @ Param ARGs */public static void main (string [] ARGs) {// todo auto-generated method stub stringdaoxu sdx = new stringdaoxu (); sdx. formatstring ("abcdefghi ");}}

Running result

2. There is a three-digit number. The single digit is C, the ten digits are B, and the hundred digits are,

In the preceding operation, how many situations does the three-digit number meet?

public class MoberTest1 { /**  * @param args  */ public static void main(String[] args) {  // TODO Auto-generated method stub  int b = 1;     for(int a=0;a<=9;a++){      for(int c=0;c<=9;c++){       if(a+c==13){        System.out.print("a="+a+" ");        System.out.print("b="+b+" ");        System.out.print("c="+c+"  ;");        System.out.println();       }      }     } }

The running result is as follows:

3. If there is a set of numbers, what is the absolute value of the maximum number and the minimum number?

package com.cn.test;public class MaxAndMin { public int ChaZhi(int[] in){  int temp = 0;  for(int i=0;i<in.length;i++){   for(int j=0;j<in.length;j++){    if(in[i]>in[j]){     temp = in[i];     in[i] = in[j];     in[j] = temp;    }   }  }//  System.out.println(in[0] - in[in.length-1]);  return Math.abs(in[0] - in[in.length-1]); } /**  * @param args  */ public static void main(String[] args) {  // TODO Auto-generated method stub  int[] in = {10,20,30,40,50,20,33,80};        MaxAndMin mam = new MaxAndMin();        mam.ChaZhi(in);        System.out.println(mam.ChaZhi(in)); }}

The running result is as follows:

4Print the 9-9 multiplication table:

Package com.cn. test; public class jiujiu multiplication {public static void main (string [] ARGs) {for (INT I = 1; I <= 9; I ++) {for (Int J = 1; j <= I; j ++) {system. out. print (J + "*" + I + "=" + I * j + "");} system. out. println ();}}}

The running result is as follows:

5. Use recursion to find the factorial of a number?

Package com.cn. test; public class diguitext {/*** @ Param ARGs */public static void main (string [] ARGs) {// todo auto-generated method stub diguitext DG = new diguitext (); system. out. println ("10 factorial:" + DG. digui (10);} public long digui (int n) {If (n = 1) {return 1;} else {return N * digui (n-1 );}}}

The result is as follows: