JAVA最简单算法题合集

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public class Test {
	public static void main(String[] args) {
		int[] arraytest = { 1 , 9 , 9 , 0 , 9 , 6 , 0 , 5 } ;
		for (int i = 0; i < arraytest.length; i++) {
			System.out.print(arraytest[i]+" ");
		}
		System.out.println();
//		new Test().selectsort(arraytest);
		new Test().pullsort(arraytest);
		for (int i = 0; i < arraytest.length; i++) {
			System.out.print(arraytest[i]+" ");
		}
	}
	public void selectsort(int[] arraytest){
		int temp ;
		for (int i = 0; i < arraytest.length; i++) {
			for (int j = i+1; j < arraytest.length; j++) {
				//依次与后面的数比较，最后把最小的数交换
				if(arraytest[j]<arraytest[i]){
					temp = arraytest[i] ;
					arraytest[i] = arraytest[j];
					arraytest[j] = temp ;
				}
			}
		}		
	}
	public void pullsort(int[] arraytest){
		int temp ;
		for (int i = 0; i < arraytest.length; i++) {
			for (int j = 0; j < arraytest.length-i-1; j++) {
				//把相邻两个数据比较
				if(arraytest[j]>arraytest[j+1]){
				//看是从大到小排序还是从小到大排序看temp的值赋给了谁，所以这里是从小到大排序	
					temp = arraytest[j] ;
					arraytest[j] = arraytest[j+1] ;
					arraytest[j+1] = temp ;
				}
			}
		}		
	}
}

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public class SplitBy2{

    static int num=12;

    static int[] arr={1,3,7,11,12,17,23,25,27};

    static int start,end,index;

   public static void main(String[] args){

     System.out.println(splitBy2(arr,num));

 }

   public static int splitBy2(int arr[],int num){

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       start=0;

       end=arr.length-1;

     while(true){

     index=(start+end)/2;

     if(arr[index]==num){

      return index;

     }else if(start>end){

      System.out.println("没有找到");

      return -1;

    }else{

      if(arr[index]>num){

       end=index-1;

       }

      if(arr[index]<num){

       start=index+1;
       }
     }
   }
  }
}