站長資訊網(wǎng)對已經(jīng)排好序的數(shù)組適用
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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("沒有找到"); |
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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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} |
