Update README.md, LeetCode/14.java files

LeetCode/14.java

+class Solution {
+
+    
+    public String longestCommonPrefix(String[] strs) {
+
+        if (strs == null || strs.length == 0) {
+            return "";
+        }
+        int minLength = strs[0].length();
+        for (String s : strs) {
+            minLength = Math.min(minLength, s.length());
+        }
+
+        int l = 0;
+        int r = minLength;
+
+        while (l <= r) {
+            int mid = (l + r) / 2;
+            String candidate = strs[0].substring(0, mid);
+            if (bs(candidate, strs)) {
+                l = mid + 1;
+            } else {
+                r = mid - 1;
+            }
+        }
+        return strs[0].substring(0, (l + r) / 2);
+
+    }
+
+    private boolean bs(String candidate, String[] strs) {
+        System.out.println(candidate);
+
+        for (String s : strs) {
+            if (!s.startsWith(candidate)) {
+                return false;
+            }
+        }
+        return true;
+    }
+}

README.md

@@ -280,6 +280,7 @@ Use search to find what you want to see. Recommended to use https://record.jxtxz
 | LeetCode   | 11               | Container With Most Water                                    | 双指针              | 暴力                                          |          |
 | LeetCode   | 12               | Integer to Roman                                             |                     |                                               | java     |
 | LeetCode   | 13               | Roman to Integer                                             |                     |                                               | java     |
+| LeetCode   | 14               | Longest Common Prefix                                        |                     | 二分                                           | java     |
 | LeetCode   | 15               | 3Sum                                                         |                     |                                               | java     |
 | LeetCode   | 17               | Letter Combinations of a Phone Number                        |                     | 递归                                              | java     |
 | LeetCode   | 18               | 4Sum                                                         |                     |                                              | java      |