Create closest-equal-element-queries.cpp

Author: kamyu104

C++/closest-equal-element-queries.cpp

@@ -0,0 +1,33 @@
+// Time:  O(n)
+// Space: O(n)
+
+// hash table
+class Solution {
+public:
+    vector<int> solveQueries(vector<int>& nums, vector<int>& queries) {
+        vector<int> dist(size(nums), size(nums));
+        unordered_map<int, int> left;
+        for (int i = 0; i < 2 * size(nums) - 1; ++i) {
+            const auto& x = nums[i % size(nums)];
+            if (left.count(x)) {
+                dist[i % size(nums)] = min(dist[i % size(nums)], i - left[x]);
+            }
+            left[x] = i;
+        }
+        unordered_map<int, int> right;
+        for (int i = 2 * size(nums) - 2; i >= 0; --i) {
+            const auto& x = nums[i % size(nums)];
+            if (right.count(x)) {
+                dist[i % size(nums)] = min(dist[i % size(nums)], right[x] - i);
+            }
+            right[x] = i;
+        }
+        vector<int> result(size(queries), -1);
+        for (int i = 0; i < size(queries); ++i) {
+            if (dist[queries[i]] < size(nums)) {
+                result[i] = dist[queries[i]];
+            }
+        }
+        return result;
+    }
+};