add

5.leetcode/src/com/fanxb/common/offer/Q53.java

@@ -0,0 +1,49 @@
+package com.fanxb.common.offer;
+
+/**
+ * 两数相加
+ *
+ * @author fanxb
+ * @date 2021/6/1
+ **/
+public class Q53 {
+
+    public int search(int[] nums, int target) {
+        if (nums.length == 0) {
+            return 0;
+        }
+        //二分查找目标值在数组中的位置
+        int l = 0, r = nums.length - 1;
+        while (l < r) {
+            if (nums[l] == target) {
+                break;
+            }
+            int mid = (l + r) / 2;
+            if (nums[mid] == target) {
+                l = mid;
+                break;
+            }
+            if (nums[mid] < target) {
+                l = mid + 1;
+            } else {
+                r = mid - 1;
+            }
+        }
+        if (nums[l] != target) {
+            return 0;
+        }
+        int index = l, res = 1;
+        //找左边的
+        while (--index > 0 && nums[index] == target) {
+            res++;
+        }
+        while (++l < nums.length && nums[l] == target) {
+            res++;
+        }
+        return res;
+    }
+
+    public static void main(String[] args) {
+        System.out.println(new Q53().search(new int[]{5, 7, 7, 8, 8, 10}, 6));
+    }
+}

5.leetcode/src/com/fanxb/common/offer/package-info.java

@@ -0,0 +1,4 @@
+package com.fanxb.common.offer;
+/**
+ * 剑指offer相关题目
+ */