publicclassSolution{ publicintGetNumberOfK(int [] array , int k){ if(array==null||array.length==0) return0; int l = binarySearch(array, k); int h = binarySearch(array, k+1); return (l>array.length-1 || array[l]!=k)?0:h-l; } privateintbinarySearch(int[] n, int k){ int l = 0, r = n.length; int m; while(l<r){ m = (r+l)/2; if(n[m]>=k) // 保证最后的位置等于或小于查找的元素 r=m; else l=m+1; } return l; } }