solve problem Positions Of Large Groups

Author: P-ppc

README.md

@@ -131,6 +131,7 @@ All solutions will be accepted!
 |415|[Add Strings](https://leetcode-cn.com/problems/add-strings/description/)|[java/py/js](./algorithms/AddStrings)|Easy|
 |67|[Add Binary](https://leetcode-cn.com/problems/add-binary/description/)|[java/py/js](./algorithms/AddBinary)|Easy|
 |504|[Base 7](https://leetcode-cn.com/problems/base-7/description/)|[java/py/js](./algorithms/Base7)|Easy|
+|830|[Positions Of Large Groups](https://leetcode-cn.com/problems/positions-of-large-groups/description/)|[java/py/js](./algorithms/PositionsOfLargeGroups)|Easy|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/PositionsOfLargeGroups/README.md

@@ -0,0 +1,2 @@
+# Positions Of Large Groups
+This problem is easy to solve

algorithms/PositionsOfLargeGroups/Solution.java

@@ -0,0 +1,31 @@
+class Solution {
+    public List<List<Integer>> largeGroupPositions(String S) {
+        Character lastCharacter = null;
+        List<List<Integer>> res = new ArrayList<List<Integer>>();
+        int start = 0,
+            end = 0;
+        
+        for (int i = 0; i < S.length(); i++) {
+            if (lastCharacter == null || lastCharacter.equals(S.charAt(i))) {
+                end = i;
+            } else {
+                if (end - start + 1 >= 3) {
+                    List<Integer> group = new ArrayList<Integer>();
+                    group.add(start);
+                    group.add(end);
+                    res.add(group);
+                }
+                end = start = i;
+            }
+            lastCharacter = S.charAt(i);
+        }
+        
+        if (end - start + 1 >= 3) {
+            List<Integer> group = new ArrayList<Integer>();
+            group.add(start);
+            group.add(end);
+            res.add(group);
+        }
+        return res;
+    }
+}

algorithms/PositionsOfLargeGroups/solution.js

@@ -0,0 +1,28 @@
+/**
+ * @param {string} S
+ * @return {number[][]}
+ */
+var largeGroupPositions = function(S) {
+    let lastCharacter = null,
+        start = 0,
+        end = 0,
+        res = []
+    
+    for (let i = 0; i < S.length; i++) {
+        if (lastCharacter === null || lastCharacter === S[i]) {
+            end = i
+        } else {
+            if (end - start + 1 >= 3) {
+                res.push([start, end])
+            }
+            end = start = i
+        }
+        lastCharacter = S[i]
+    }
+    
+    if (end - start + 1 >= 3) {
+        res.push([start, end])
+    }
+    
+    return res
+};

algorithms/PositionsOfLargeGroups/solution.py

@@ -0,0 +1,25 @@
+class Solution(object):
+    def largeGroupPositions(self, S):
+        """
+        :type S: str
+        :rtype: List[List[int]]
+        """
+        last_character = None
+        start = 0
+        end = 0
+        res = []
+        
+        for i in range(len(S)):
+            if last_character == None or last_character == S[i]:
+                end = i
+            else:
+                count = end - start + 1
+                if count >= 3:
+                    res.append([start, end])
+                end = start = i
+            last_character = S[i]
+        
+        if end - start + 1 >= 3:
+            res.append([start, end])
+        
+        return res