配列の二分割検索---要素の最初と最後の出現の位置と要素の保存を検索します。


package searching;

public class BinSearch_ {

	/**
	 * binSearch:      ,           
	 * InsertToArray:         ,       
	 * binSearchFirst:              
	 * binSearchLast:               
	 */
	public static void main(String[] args) {
		int[] a={3,5,10,10,10,13,13,19,23};
		System.out.println(binSearch(a,23));	 	//8
		System.out.println(InsertToArray(a,1));		//0
		System.out.println(InsertToArray(a,4));		//1
		System.out.println("first:"+binSearchFirst(a,10));//2
		System.out.println("first:"+binSearchLast(a,10));//4
	}

	private static int binSearch(int[] a, int key) {
		// TODO Auto-generated method stub
		int min=0,max=a.length-1;
		int mid=(max+min)/2;
		while(min<=max){
			mid=(max+min)/2;
			if (key>a[mid]) {
				min=mid+1;
			}else if (keya[mid]{}
min=mid+1
}else if(keya[mid]{}
min=mid+1
}else{
max=mid;
)
if(max=min){
break;
)
)
if(a[min]!=key){//    が  しない  は-1に ります。
return-1;
}else{
return min
)
)
prvate static int binSearch Last(int[]a,int key){
//TODO Auto-generatod method stub
int min=0,max=a.length-1;
int mid=0
while(min<=max){
mid=(max+min+1)/2
if(key)=a[mid]
min=mid
}else{
max=mid-1;
)
if(max=min){
break;
)
)
if(a[max]!=key){/    が  しない  は-1を します。
return-1;
}else{
return max;
)
)
)