solve problem Convert A Number To Hexadecimal

Author: P-ppc

README.md

@@ -118,6 +118,7 @@ All solutions will be accepted!
 |744|[Find Smallest Letter Greater Than Target](https://leetcode-cn.com/problems/find-smallest-letter-greater-than-target/description/)|[java/py/js](./algorithms/FindSmallestLetterGreaterThanTarget)|Easy|
 |203|[Remove Linked List Elements](https://leetcode-cn.com/problems/remove-linked-list-elements/description/)|[java/py/js](./algorithms/RemoveLinkedListElements)|Easy|
 |237|[Delete Node In A Linked List](https://leetcode-cn.com/problems/delete-node-in-a-linked-list/description/)|[java/py/js](./algorithms/DeleteNodeInALinkedList)|Easy|
+|405|[Convert A Number To Hexadecimal](https://leetcode-cn.com/problems/convert-a-number-to-hexadecimal/description/)|[java/py/js](./algorithms/ConvertANumberToHexadecimal)|Easy|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/ConvertANumberToHexadecimal/README.md

@@ -0,0 +1,2 @@
+# Convert A Number To Hexadecimal
+This problem is easy to solve by bitwise, pay attention to the bit spillover

algorithms/ConvertANumberToHexadecimal/Solution.java

@@ -0,0 +1,28 @@
+class Solution {
+    public String toHex(int num) {
+        long longNum = num;
+        if (longNum == 0) {
+            return "0";
+        }
+        
+        if (longNum < 0) {
+            // use 4294967295L to replace 0xffffffff
+            // because 0xffffffff in java is -1
+            longNum = 4294967295L + num + 1;
+        }
+        
+        String res = "";
+        
+        while (longNum > 0) {
+            int mod = (int) (longNum % 16);
+            if (mod >= 10) {
+                res = String.valueOf(((char)(mod + 87))) + res;
+            } else {
+                res = String.valueOf(mod) + res;
+            }
+            longNum = longNum / 16L;            
+        }
+        
+        return res;
+    }
+}

algorithms/ConvertANumberToHexadecimal/solution.js

@@ -0,0 +1,29 @@
+/**
+ * @param {number} num
+ * @return {string}
+ */
+var toHex = function(num) {
+    if (num === 0) {
+        return '0'
+    }
+    
+    if (num < 0) {
+        // use + replace ^
+        // + means - abs of num
+        num = 0xffffffff + num + 1
+    }
+    
+    let res = ''
+    while (num > 0) {
+        let mod = num % 16
+        if (mod >= 10) {
+            res = String.fromCharCode(mod + 87) + res
+        } else {
+            res = String(mod) + res
+        }
+        
+        num = parseInt(num / 16)
+    }
+    
+    return res
+};

algorithms/ConvertANumberToHexadecimal/solution.py

@@ -0,0 +1,20 @@
+class Solution(object):
+    def toHex(self, num):
+        """
+        :type num: int
+        :rtype: str
+        """
+        if num == 0:
+            return '0'
+        
+        if num < 0:
+            num = (-num ^ 0xffffffff) + 1
+        res = ''
+        while num > 0:
+            mod = num % 16
+            if mod >= 10:
+                res = chr(mod + 87) + res
+            else:
+                res = str(mod) + res
+            num = num / 16
+        return res