站长资讯网对已经排好序的数组适用
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public class SplitBy2{ |
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static int num=12; |
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static int[] arr={1,3,7,11,12,17,23,25,27}; |
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static int start,end,index; |
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public static void main(String[] args){ |
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System.out.println(splitBy2(arr,num)); |
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} |
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public static int splitBy2(int arr[],int num){ |
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start=0; |
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end=arr.length-1; |
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while(true){ |
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index=(start+end)/2; |
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if(arr[index]==num){ |
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return index; |
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}else if(start>end){ |
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System.out.println("没有找到"); |
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return -1; |
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}else{ |
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if(arr[index]>num){ |
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end=index-1; |
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} |
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if(arr[index]<num){ |
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start=index+1; |
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} |
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} |
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} |
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} |
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} |
