华为机考
1. 判断回文public class Huiwen {
static boolean IsHuiwen(String org){
StringBuffer strBf = new StringBuffer(org);
StringBuffer strBfv = strBf.reverse();
System.out.println("Org:"+org);
System.out.println("OrgRe:"+strBfv);
return org.equals(strBfv.toString()); //一定要用org，不能用strBf
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(IsHuiwen("abcba"));
}
}
2. 求数组中大于平均值的个数
3. 单链表逆置
public class LinkReserve {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
class Node{
String value;
Node next;
public Node(String value){
this.value = value;
}
}
Node n1 = new Node("a");
Node n2 = new Node("b");
Node n3 = new Node("c");
Node n4 = new Node("d");
n1.next = n2;
n2.next = n3;
n3.next = n4;
Node head = n1;
Node pre = null;
Node next = head.next;
head.next = pre;
while(next != null){
pre = head;
head = next;
next = next.next;
head.next = pre;
}
Node p = head;
while(p != null){
System.out.println(p.value);
p = p.next;
}
}
}
4. 树的遍历
5. 大数相加
[*]import java.io.BufferedReader;
[*]import java.io.IOException;
[*]import java.io.InputStreamReader;
[*]import java.util.StringTokenizer;
[*]
[*]public class BigIntegerOperation {
[*]
[*]
[*] public static void main(String[] args) throws IOException {
[*]
[*] /**
[*] * 从控制台读取输入数据 格式为 num1空格num2 为空则exit
[*] */
[*] BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
[*] String str = in.readLine();
[*] while(str!=null){
[*] StringTokenizer st = new StringTokenizer(str," ");
[*] String num1 = st.nextToken();
[*] String num2 = st.nextToken();
[*] int len1 = num1.length();
[*] int len2 = num2.length();
[*] /**
[*] * 将不等长的两输入字符串格式化，比如 num1 = 123 num2 = 1234
[*] * 经格式化后将成为num1 = 0123 num2 = 1234为方便计算
[*] */
[*] if(len1 > len2){
[*] for(int i=0; i< len1-len2; i++){
[*] num2 = "0"+num2;
[*] }
[*] }else if(len2>len1){
[*] for(int i=0; i< len2-len1; i++){
[*] num1 = "0"+num1;
[*] }
[*] }
[*]
[*] int[] arr1 = BigIntegerOperation.str2intArr(num1);
[*] int[] arr2 = BigIntegerOperation.str2intArr(num2);
[*]
[*] arr1 = BigIntegerOperation.reverse(arr1);
[*] arr2 = BigIntegerOperation.reverse(arr2);
[*]
[*]
[*] int[] result = BigIntegerOperation.add(arr1, arr2);
[*]
[*]// System.out.print(num1 +" + " + num2 +" = ");
[*] for(int i=result.length-1; i>=0; i--){
[*] if(i == result.length-1 && result == 0) continue;
[*] System.out.print(result);
[*] }
[*] str = in.readLine();
[*] }
[*] }
[*]
[*] /**
[*] * 倒置数组元素
[*] */
[*] public static int [] reverse(int[] arr){
[*] int len = arr.length;
[*] for(int i = 0,j = len-1; i<j; i++,j--){
[*] int temp = arr;
[*] arr = arr;
[*] arr = temp;
[*] }
[*] return arr;
[*] }
[*]
[*] /**
[*] * 将字符串转换成整型数组
[*] */
[*] public static int [] str2intArr(String str){
[*] int len = str.length();
[*] int [] arr = new int;
[*] for(int i = 0 ; i<len; i++){
[*] arr = str.charAt(i) - '0' ;
[*] }
[*] return arr;
[*] }
[*]
[*] /**
[*] * 核心方法 两个整型数组相加
[*] */
[*] public static int [] add(int a[], int b[]){
[*] int maxLen = a.length;
[*] int[] sum = new int1];
[*]
[*] for(int i = 0; i< maxLen ; i++){
[*] int tempSum = a + b;
[*] sum += tempSum%10;
[*] int d = tempSum/10; //进位
[*] sum1] += d;
[*] }
[*] return sum;
[*] }
[*]
[*]}
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