Create degree-of-an-array.cpp

Author: kamyu104

C++/degree-of-an-array.cpp

@@ -0,0 +1,29 @@
+// Time:  O(n)
+// Space: O(n)
+
+class Solution {
+public:
+    int findShortestSubArray(vector<int>& nums) {
+        unordered_map<int, int> left, right;
+        unordered_map<int, int> counts;
+        for (int i = 0; i < nums.size(); ++i) {
+            if (left.count(nums[i]) == 0) {
+                left[nums[i]] = i;
+            }
+            right[nums[i]] = i;
+            ++counts[nums[i]];
+        }
+        auto degree = max_element(counts.begin(), counts.end(),
+                                  [](const pair<int, int>& a,
+                                     const pair<int, int>& b) {
+                                      return a.second < b.second;
+                                  })->second;
+        auto result = numeric_limits<int>::max();
+        for (const auto& kvp : counts) {
+            if (kvp.second == degree) {
+                result = min(result, right[kvp.first] - left[kvp.first] + 1);
+            }
+        }
+        return result;
+    }
+};