add 1286

Author: luliyucoordinate

README.md

@@ -584,4 +584,5 @@ LeetCode
 |1281|[Subtract the Product and Sum of Digits of an Integer](https://leetcode.com/problems/subtract-the-product-and-sum-of-digits-of-an-integer/)|c|[c++](./src/1281-Subtract-the-Product-and-Sum-of-Digits-of-an-Integer/1281.cpp)|[python](./src/1281-Subtract-the-Product-and-Sum-of-Digits-of-an-Integer/1281.py)|[go](./src/1281-Subtract-the-Product-and-Sum-of-Digits-of-an-Integer/1281.go)|[js](./src/1281-Subtract-the-Product-and-Sum-of-Digits-of-an-Integer/1281.js)|[java](./src/1281-Subtract-the-Product-and-Sum-of-Digits-of-an-Integer/1281.java)|Easy|
 |1282|[Group the People Given the Group Size They Belong To](https://leetcode.com/problems/group-the-people-given-the-group-size-they-belong-to/)|c|[c++](./src/1282-Group-the-People-Given-the-Group-Size-They-Belong-To/1282.cpp)|[python](./src/1282-Group-the-People-Given-the-Group-Size-They-Belong-To/1282.py)|[go](./src/1282-Group-the-People-Given-the-Group-Size-They-Belong-To/1282.go)|[js](./src/1282-Group-the-People-Given-the-Group-Size-They-Belong-To/1282.js)|[java](./src/1282-Group-the-People-Given-the-Group-Size-They-Belong-To/1282.java)|Medium|
 |1283|[Find the Smallest Divisor Given a Threshold](https://leetcode.com/problems/find-the-smallest-divisor-given-a-threshold/)|c|[c++](./src/1283-Find-the-Smallest-Divisor-Given-a-Threshold/1283.cpp)|[python](./src/1283-Find-the-Smallest-Divisor-Given-a-Threshold/1283.py)|[go](./src/1283-Find-the-Smallest-Divisor-Given-a-Threshold/1283.go)|[js](./src/1283-Find-the-Smallest-Divisor-Given-a-Threshold/1283.js)|[java](./src/1283-Find-the-Smallest-Divisor-Given-a-Threshold/1283.java)|Medium|
-|1284|[Minimum Number of Flips to Convert Binary Matrix to Zero Matrix](https://leetcode.com/problems/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix/)|c|[c++](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.cpp)|[python](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.py)|[go](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.go)|[js](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.js)|[java](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.java)|Hard|
+|1284|[Minimum Number of Flips to Convert Binary Matrix to Zero Matrix](https://leetcode.com/problems/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix/)|c|[c++](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.cpp)|[python](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.py)|[go](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.go)|[js](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.js)|[java](./src/1284-Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix/1284.java)|Hard|
+|1286|[Iterator for Combination](https://leetcode.com/problems/iterator-for-combination/)|c|[c++](./src/1286-Iterator-for-Combination/1286.cpp)|[python](./src/1286-Iterator-for-Combination/1286.py)|[go](./src/1286-Iterator-for-Combination/1286.go)|[js](./src/1286-Iterator-for-Combination/1286.js)|[java](./src/1286-Iterator-for-Combination/1286.java)|Easy|

src/1286-Iterator-for-Combination/1286.cpp

@@ -0,0 +1,35 @@
+class CombinationIterator 
+{
+public:
+    CombinationIterator(string ch, int l) 
+    {
+        combine(0, l, "", ch);
+    }
+    
+    string next() 
+    {
+        string res = q.front();
+        q.pop();
+        return res;
+    }
+    
+    bool hasNext() 
+    {
+        return !q.empty();
+    }
+private:
+    queue<string> q;
+    
+    void combine(int s, int k, string cur, string& ch)
+    {
+        if (cur.size() == k) {
+            q.push(cur);
+            return;
+        }
+        
+        for (int i = s; i <= ch.size() - (k - cur.size()); i++)
+        {
+            combine(i + 1, k, cur + ch[i], ch);
+        }
+    }
+};

src/1286-Iterator-for-Combination/1286.go

@@ -0,0 +1,32 @@
+type CombinationIterator struct {
+    res []string
+}
+
+func Constructor(ch string, l int) CombinationIterator {
+    data := make([]string, 0)
+    combine(0, l, "", ch, &data)
+    return CombinationIterator{res:data}
+}
+
+func combine(s, l int, cur, ch string, data *[]string) {
+    if len(cur) == l {
+        *data = append(*data, cur)
+        return
+    }
+    
+    for i := s; i <= len(ch) - (l - len(cur)); i++ {
+        combine(i + 1, l, cur + string(ch[i]), ch, data)
+    }
+}
+
+
+func (this *CombinationIterator) Next() string {
+    ret := this.res[0]
+    this.res = this.res[1:]
+    return ret
+}
+
+
+func (this *CombinationIterator) HasNext() bool {
+    return len(this.res) != 0
+}

src/1286-Iterator-for-Combination/1286.java

@@ -0,0 +1,29 @@
+class CombinationIterator {
+
+    public CombinationIterator(String ch, int l) {
+        combine(0, l, new StringBuilder(), ch);
+    }
+    
+    private Queue<String> q = new LinkedList();
+    
+    private void combine(int s, int k, StringBuilder cur, String ch) {
+        if (cur.length() == k) {
+            q.offer(cur.toString());
+            return;
+        }
+        
+        for (int i = s; i <= ch.length() - (k - cur.length()); i++) {
+            cur.append(ch.charAt(i));
+            combine(i + 1, k, cur, ch);
+            cur.deleteCharAt(cur.length() - 1);
+        }
+    }
+    
+    public String next() {
+        return q.poll();
+    }
+    
+    public boolean hasNext() {
+        return !q.isEmpty();
+    }
+}

src/1286-Iterator-for-Combination/1286.js

@@ -0,0 +1,31 @@
+/**
+ * @param {string} characters
+ * @param {number} combinationLength
+ */
+var CombinationIterator = function(ch, l) {
+    this.res = [];
+    var combine = (s, cur) => {
+        if (cur.length == l) {
+            this.res.push(cur);
+            return;
+        }
+        for (let i = s; i <= ch.length - (l - cur.length); i++) {
+            combine(i + 1, cur + ch[i]);
+        }
+    }
+    combine(0, "");
+};
+
+/**
+ * @return {string}
+ */
+CombinationIterator.prototype.next = function() {
+    return this.res.shift();
+};
+
+/**
+ * @return {boolean}
+ */
+CombinationIterator.prototype.hasNext = function() {
+    return this.res.length != 0;
+};

src/1286-Iterator-for-Combination/1286.py

@@ -0,0 +1,12 @@
+class CombinationIterator:
+    def __init__(self, ch: str, l: int):
+        self.data = itertools.combinations(ch, l)
+        self.last = ch[-l:]
+        self.res = None
+
+    def next(self) -> str:
+        self.res = "".join(next(self.data))
+        return self.res
+
+    def hasNext(self) -> bool:
+        return self.last != self.res

src/addProb.py

@@ -2,10 +2,10 @@
 import os, bisect
 
 # 题目名称
-name = "Minimum Number of Flips to Convert Binary Matrix to Zero Matrix"
-ID = 1284
-url = "https://leetcode.com/problems/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix/"
-difficult = "Hard"
+name = "Iterator for Combination"
+ID = 1286
+url = "https://leetcode.com/problems/iterator-for-combination/"
+difficult = "Medium"
 prog = ['c', 'cpp', 'py', 'go', 'js', 'java']