From 7f39523b6b2bf109fb92041e3c9215a9e31ab6f4 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Fri, 9 Oct 2020 14:52:08 +0800
Subject: import(solutions): Add problem 1286 .

---
 works/solutions/cpp/1286.cpp | 56 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 works/solutions/cpp/1286.cpp

(limited to 'works/solutions/cpp/1286.cpp')

diff --git a/works/solutions/cpp/1286.cpp b/works/solutions/cpp/1286.cpp
new file mode 100644
index 0000000..1ad0d4e
--- /dev/null
+++ b/works/solutions/cpp/1286.cpp
@@ -0,0 +1,56 @@
+#include <string>
+
+using std::string;
+
+#include <vector>
+
+class CombinationIterator {
+public:
+  string chars;
+  int char_length;
+  int combinationLength;
+  bool has_next = true;
+  std::vector<int> indices;
+
+  CombinationIterator(string characters, int combinationLength)
+      : chars(characters), char_length(characters.size()),
+        combinationLength(combinationLength) {
+    for (int i = 0; i < combinationLength; i++) {
+      indices.push_back(i);
+    }
+  }
+
+  string next() {
+    string result;
+    for (auto index : indices) {
+      result.push_back(chars[index]);
+    }
+
+    int count = 1;
+    while (indices[combinationLength - count] == char_length - count) {
+      count++;
+      if (count > combinationLength) {
+        has_next = false;
+        return result;
+      }
+    }
+
+    indices[combinationLength - count] += 1;
+    for (int i = combinationLength - count + 1; i < combinationLength; i++) {
+      indices[i] = indices[i - 1] + 1;
+    }
+
+    return result;
+  }
+
+  bool hasNext() {
+    return has_next;
+  }
+};
+
+/**
+ * Your CombinationIterator object will be instantiated and called as such:
+ * CombinationIterator* obj = new CombinationIterator(characters,
+ * combinationLength); string param_1 = obj->next(); bool param_2 =
+ * obj->hasNext();
+ */
\ No newline at end of file
-- 
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