冒泡排序

import java.util.Arrays;

public class MaoPaoPaiXu {
	public static void main(String[] args) {
		int[] value = {1,5,8,7,6,4,0,5,8,4,6};
		sort(value);
		System.out.println(Arrays.toString(value));
	}
	public static void sort(int value[]){
		//temp 存儲最小變量
		int temp;
		for (int i = 0; i < value.length; i++) {
			for (int j = 0; j < value.length-1-i; j++) {
				//按照大小替換位置
				if (value[j]>value[j+1]) {
					temp=value[j];
					value[j]=value[j+1];
					value[j+1]=temp;
				}
			}
		}
		
	}
}

数组填充

public class MyFill {
	public static void myFill(int[] a,int start,int end,int key){
		for (int i = start; i < end; i++) {
			a[i] = key;
		}
	}
}

二分法查找

/**
 * 二分法查找
 * @author Administrator
 *
 */
public class BinarySearch {
	public static int myBinarySearch(int[] a, int key) {
		int start = 0;
		int end = a.length - 1;
		while (start <= end) {
			// >>>带符号右移
			int mid = (end + start) >>> 1;
			int midValue = a[mid];

			if (midValue < key) 
				start = mid + 1;
			 else if (midValue > key)
				end = mid - 1;
			 else 
				return mid;

		}
		return -1;
	}
}

数组排序与二分法查找的应用

import java.util.Arrays;
/**
 * 数组排序与数据查询
 * @author Administrator
 *
 */
public class MySort {
	public static void main(String[] args) {
		int [] a = {1,5,4,78,51,11,888,7,9};
		//增强的for循环,等价于遍历数组
		/*for (int i = 0; i < a.length; i++) {
			int m = a[i];
			System.out.println(m);
		}*/
		for (int m : a) {
			System.out.println(m);
		}
		System.out.println(find(a, 78));
		MyFill.myFill(a, 1, 3, 5);
		System.out.println(Arrays.toString(a));
		sort(a);
		System.out.println(Arrays.toString(a));
		System.out.println(BinarySearch.myBinarySearch(a, 51));
		
	
}
	//排序
	public static void sort(int[] a){
		int temp;
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a.length-1-i; j++) {
				if (a[j]>a[j+1]) {
					temp = a[j];
					a[j] = a[j+1];
					a[j+1] = temp;
				}
			}
		}
		
	}
	//逐个查找
	public static  int find(int[] a,  int s){
		for (int i = 0; i < a.length; i++) {
			if (s==a[i]) {
				return i;
			}
		}
		return -1;
	}
}