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如果数组是无序的不能使用二分查找。
package StringBufferPackage;
public class Demo8_getIndex {
public static void main(String[] args) {
int[] arr = {11,22,33,44,55,66,77};
System.out.println(getIndex(arr,55));
}
private static int getIndex(int[] arr, int value) {
int min = 0;
int max = arr.length - 1;
int mid = (min + max) / 2;
while(arr[mid] != value) {
if(arr[mid] > value) {
max = mid - 1;
} else if (arr[mid] < value) {
min = mid + 1;
}
mid = (min + max) / 2;
if (min > max) {
return 0;
}
}
return mid;
}
}