0066. Plus One

Author: coderbean

markdown/0066. Plus One.md

@@ -0,0 +1,58 @@
+### [66\. Plus One](https://leetcode.com/problems/plus-one/)
+
+Difficulty: **Easy**
+
+
+Given a **non-empty** array of digits representing a non-negative integer, plus one to the integer.
+
+The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a single digit.
+
+You may assume the integer does not contain any leading zero, except the number 0 itself.
+
+**Example 1:**
+
+```
+Input: [1,2,3]
+Output: [1,2,4]
+Explanation: The array represents the integer 123.
+```
+
+**Example 2:**
+
+```
+Input: [4,3,2,1]
+Output: [4,3,2,2]
+Explanation: The array represents the integer 4321.
+```
+
+
+#### Solution
+
+Language: **Java**
+
+```java
+class Solution {
+    public int[] plusOne(int[] digits) {
+        if (digits == null || digits.length == 0) {
+            int[] result = {1};
+            return result;
+        }
+        int plusNum = 1;
+        for (int i = digits.length - 1; i >= 0 && plusNum > 0; i--) {
+            int newNum = digits[i] + plusNum;
+            plusNum = newNum / 10;
+            digits[i] = newNum % 10;
+        }
+        if (plusNum > 0) {
+            int[] result = new int[digits.length + 1];
+            result[0] = plusNum;
+            for (int i = 0; i < digits.length; i++) {
+                result[i + 1] = digits[i];
+            }
+            return result;
+        }
+        return digits;
+    }
+}
+```
+![](https://raw.githubusercontent.com/PicGoBed/PicBed/master/20190719172019.png)

src/main/java/leetcode/_66_/Main.java

@@ -0,0 +1,16 @@
+package leetcode._66_;
+
+import leetcode.common.Printer;
+
+/**
+ * Created by zhangbo54 on 2019-03-04.
+ */
+public class Main {
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+        int[] digits = {1, 2, 3};
+        int[] ints = solution.plusOne(digits);
+        Printer.printArrays(ints);
+    }
+}
+

src/main/java/leetcode/_66_/Solution.java

@@ -0,0 +1,25 @@
+package leetcode._66_;
+
+class Solution {
+    public int[] plusOne(int[] digits) {
+        if (digits == null || digits.length == 0) {
+            int[] result = {1};
+            return result;
+        }
+        int plusNum = 1;
+        for (int i = digits.length - 1; i >= 0 && plusNum > 0; i--) {
+            int newNum = digits[i] + plusNum;
+            plusNum = newNum / 10;
+            digits[i] = newNum % 10;
+        }
+        if (plusNum > 0) {
+            int[] result = new int[digits.length + 1];
+            result[0] = plusNum;
+            for (int i = 0; i < digits.length; i++) {
+                result[i + 1] = digits[i];
+            }
+            return result;
+        }
+        return digits;
+    }
+}

src/main/java/leetcode/_66_/solution.md

@@ -0,0 +1,58 @@
+### [66\. Plus One](https://leetcode.com/problems/plus-one/)
+
+Difficulty: **Easy**
+
+
+Given a **non-empty** array of digits representing a non-negative integer, plus one to the integer.
+
+The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a single digit.
+
+You may assume the integer does not contain any leading zero, except the number 0 itself.
+
+**Example 1:**
+
+```
+Input: [1,2,3]
+Output: [1,2,4]
+Explanation: The array represents the integer 123.
+```
+
+**Example 2:**
+
+```
+Input: [4,3,2,1]
+Output: [4,3,2,2]
+Explanation: The array represents the integer 4321.
+```
+
+
+#### Solution
+
+Language: **Java**
+
+```java
+class Solution {
+    public int[] plusOne(int[] digits) {
+        if (digits == null || digits.length == 0) {
+            int[] result = {1};
+            return result;
+        }
+        int plusNum = 1;
+        for (int i = digits.length - 1; i >= 0 && plusNum > 0; i--) {
+            int newNum = digits[i] + plusNum;
+            plusNum = newNum / 10;
+            digits[i] = newNum % 10;
+        }
+        if (plusNum > 0) {
+            int[] result = new int[digits.length + 1];
+            result[0] = plusNum;
+            for (int i = 0; i < digits.length; i++) {
+                result[i + 1] = digits[i];
+            }
+            return result;
+        }
+        return digits;
+    }
+}
+```
+![](https://raw.githubusercontent.com/PicGoBed/PicBed/master/20190719172019.png)

src/main/java/leetcode/common/Printer.java

@@ -0,0 +1,18 @@
+package leetcode.common;
+
+/**
+ * Created by zhangbo54 on 2019-07-19.
+ */
+public class Printer {
+    public static void printArrays(int[] arrays) {
+        if (arrays == null) {
+            System.out.println("[]");
+            return;
+        }
+        System.out.print("[");
+        for (int i = 0; i < arrays.length - 1; i++) {
+            System.out.print(arrays[i] + ",");
+        }
+        System.out.print(arrays[arrays.length - 1] + "]");
+    }
+}