代码
public class Test { public static void main(String[] args) { int [] a = {1,2,3,4,5,6,7,9}; boolean flag = exists(a,10); System.out.println(flag); } public static boolean exists(int [] arr, int num){ if(arr==null || arr.length==0) return false; int L = 0; int R = arr.length-1; while (L < R){ int mid = L + ((R-L)>>1); if (arr[mid] == num) return true; else if(arr[mid] > num) R = mid -1; else L = mid +1; } return arr[L] == num; } }
