特定字符輸出及二分查找 簡單面試編程題

特定字符輸出字符，如下所示：

input num ：=2

output：as follow

layer 1
*
layer 2
*
***

input num ：=4

output：as follow

layer 1
*
layer 2
*
***
layer 3
*
***
*****
layer 4
*
***
*****
*******

package com.java.interview.t_20140813;

import java.awt.DisplayMode;
import java.util.Scanner;

/**
* name: Test_Show.java
*
* date:2014-8-13 19:25:37
*
* function: output the special signals
*
* copyright: open
*
* @author wangxin
*
*/
public class Test_Show {
public static void main(String[] args) {
while (true) {
System.out
.println("Please input the num that you want to get! (< 0 to end)");
Scanner sc = new Scanner(System.in);
int num = sc.nextInt();
if (num <= 0) {
System.out.println("Error input, end the program!");
break;
} else {
// show(num);
display(num);
}
}
}

private static void display(int num) {
for (int i = 0; i < num; i++) {
System.out.println("layer " + (i + 1));
show(i + 1);
}
}

private static void show(int num) {
for (int i = 0; i < num; i++) {
show_blank(num - i - 1);
show_singal(i + 1);
show_blank(num - i - 1);
System.out.println();
}
}

private static void show_singal(int num) {
for (int i = 0; i < 2 * num - 1; i++) {
System.out.print("*");
}
// System.out.println();
}

private static void show_blank(int num) {
for (int i = 0; i < num; i++) {
System.out.print(" ");
}
}
}

二分法查找給定元素的位置<升序default>：

遞歸：

private static int binarySearch(List<Integer> list, int key, int low,
int high) {
if (low > high)
return -1;
int mid = (low + high) / 2;
if (list.get(mid) == key) {
return mid;
} else if (list.get(mid) < key) {
return binarySearch(list, key, mid + 1, high);
} else {
return binarySearch(list, key, low, mid - 1);
}
}

非遞歸：

public static int binary_Search(int[] array, int value) {
int low = 0;
int high = array.length - 1;
while (low <= high) {
int middle = (low + high) / 2;
if (value == array[middle]) {
return middle;
}
if (value > array[middle]) {
low = middle + 1;
}
if (value < array[middle]) {
high = middle - 1;
}
}
return -1;
}

Golang二分查找算法的簡單實現 http://www.linuxidc.com/Linux/2014-02/96093.htm

二分查找改進版 http://www.linuxidc.com/Linux/2013-10/91721.htm

二分查找的實現及注意事項 http://www.linuxidc.com/Linux/2013-07/87308.htm

用Python實現二分查找 http://www.linuxidc.com/Linux/2012-12/75948.htm

二分查找之Java實現 http://www.linuxidc.com/Linux/2012-05/59869.htm

Java針對數組的普通查找法和二分查找法 http://www.linuxidc.com/Linux/2012-03/57065.htm