solves ranges summary

Author: anishLearnsToCode

Diff for: README.md

@@ -1,8 +1,8 @@
 # LeetCode Algorithms
 
-![problems-solved](https://img.shields.io/badge/Problems%20Solved-143/1571-1f425f.svg)
-![problems-solved-java](https://img.shields.io/badge/Java-143/1571-1abc9c.svg)
-![problems-solved-python](https://img.shields.io/badge/Python-143/1571-1abc9c.svg)
+![problems-solved](https://img.shields.io/badge/Problems%20Solved-161/2081-1f425f.svg)
+![problems-solved-java](https://img.shields.io/badge/Java-161/2081-1abc9c.svg)
+![problems-solved-python](https://img.shields.io/badge/Python-161/2081-1abc9c.svg)
 [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](CONTRIBUTING.md)
 [![cp](https://img.shields.io/badge/also%20see-Competitve%20Programming-1f72ff.svg)](https://github.com/anishLearnsToCode/competitive-programming)
 
@@ -68,6 +68,7 @@
 | 219 | [Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii) | [![Java](assets/java.png)](src/ContainsDuplicateII.java) [![Python](assets/python.png)](python/contains_duplicate_ii.py) |
 | 225 | [Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues) | [![Java](assets/java.png)](src/MyStack.java) [![Python](assets/python.png)](python/implement_stack_using_queues.py) |
 | 226 | [Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree) | [![Java](assets/java.png)](src/InvertBinaryTree.java) [![Python](assets/python.png)](python/invert_binary_tree.py) |
+| 226 | [Summary Ranges](https://leetcode.com/problems/summary-ranges/) | [![Java](assets/java.png)](src/SummaryRanges.java) [![Python](assets/python.png)](python/summary_ranges.py) |
 | 231 | [Power of Two](https://leetcode.com/problems/power-of-two) | [![Java](assets/java.png)](src/PowerOf2.java) [![Python](assets/python.png)](python/is_power_of_2.py) |
 | 232 | [Implement Queue Using Stacks](https://leetcode.com/problems/implement-queue-using-stacks) | [![Java](assets/java.png)](src/MyQueue.java) [![Python](assets/python.png)](python/implement_queue_using_stacks.py) | 
 | 234 | [Palindrome Linked Lists](https://leetcode.com/problems/palindrome-linked-list) | [![Java](assets/java.png)](src/PalindromeLinkedList.java) [![Python](assets/python.png)](python/palindrome_linked_list.py) | 

Diff for: python/summary_ranges.py

@@ -0,0 +1,18 @@
+from typing import List
+
+
+class Solution:
+    def getRangeString(self, start: int, end: int) -> str:
+        return f'{start}' if start == end else f'{start}->{end}'
+
+    def summaryRanges(self, array: List[int]) -> List[str]:
+        if len(array) == 0: return []
+        result = []
+        startIndex, index = 0, 1
+        while index < len(array):
+            if array[index] > array[startIndex] + (index - startIndex):
+                result.append(self.getRangeString(array[startIndex], array[index - 1]))
+                startIndex = index
+            index += 1
+        result.append(self.getRangeString(array[startIndex], array[len(array) - 1]))
+        return result

Diff for: src/RobotReturnToOrigin.java

@@ -3,10 +3,10 @@ public boolean judgeCircle(String moves) {
         int vertical = 0, horizontal = 0;
         for (int index = 0 ; index < moves.length() ; index++) {
             switch (moves.charAt(index)) {
-                case 'U' -> vertical++;
-                case 'R' -> horizontal++;
-                case 'D' -> vertical--;
-                case 'L' -> horizontal--;
+                case 'U': vertical++; break;
+                case 'R': horizontal++; break;
+                case 'D': vertical--; break;
+                case 'L': horizontal--; break;
             }
         }
         return vertical == 0 && horizontal == 0;

Diff for: src/SummaryRanges.java

@@ -0,0 +1,23 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class SummaryRanges {
+
+    private String getRangeString(int start, int end) {
+        return end == start ? start + "" : start + "->" + end;
+    }
+
+    public List<String> summaryRanges(int[] array) {
+        if (array.length == 0) return new ArrayList<>();
+        List<String> result = new ArrayList<>();
+        int startIndex = 0;
+        for (int index = 1 ; index < array.length ; index++) {
+            if (array[index] > array[startIndex] + (index - startIndex)) {
+                result.add(getRangeString(array[startIndex], array[index - 1]));
+                startIndex = index;
+            }
+        }
+        result.add(getRangeString(array[startIndex], array[array.length - 1]));
+        return result;
+    }
+}

Diff for: src/TwoSumIVInputIsABST.java

@@ -1,18 +1,6 @@
 import java.util.HashSet;
 import java.util.Set;
 
-class TreeNode {
-    int val;
-    TreeNode left;
-    TreeNode right;
-    TreeNode() {}
-    TreeNode(int val) { this.val = val; }
-    TreeNode(int val, TreeNode left, TreeNode right) {
-        this.val = val;
-        this.left = left;
-        this.right = right;
-    }
-}
 
 public class TwoSumIVInputIsABST {
     Set<Integer> elements = new HashSet<>();