Solution

Method 1 – Hash Map + Binary Search

Intuition

For each value in nums, store all its indices. For each query, use binary search to find the closest index (other than itself) with the same value, considering the circular nature of the array.

Approach

Build a hash map from value to a sorted list of indices where it appears.
For each query index q, get the list of indices for nums[q].
If the list has only one index, answer is -1.
Use binary search to find the closest index to q in the list (excluding itself).
Compute the circular distance for both the next and previous indices in the list.
Return the minimum such distance for each query.

Code

[{"language":"C++","code":"class Solution {\npublic:\n    vector<int> closestEqualElementQueries(vector<int>& nums, vector<int>& queries) {\n        int n = nums.size();\n        unordered_map<int, vector<int>> pos;\n        for (int i = 0; i < n; ++i) pos[nums[i]].push_back(i);\n        vector<int> ans;\n        for (int q : queries) {\n            auto& v = pos[nums[q]];\n            if (v.size() == 1) { ans.push_back(-1); continue; }\n            auto it = lower_bound(v.begin(), v.end(), q);\n            int d1 = INT_MAX, d2 = INT_MAX;\n            if (it != v.end() && *it != q) d1 = min(abs(*it - q), n - abs(*it - q));\n            if (it != v.begin()) {\n                int prev = *(--it);\n                if (prev != q) d2 = min(abs(prev - q), n - abs(prev - q));\n            }\n            ans.push_back(min(d1, d2));\n        }\n        return ans;\n    }\n};","lang":"cpp","html":"<pre class=\"shiki shiki-themes github-light github-dark\" style=\"background-color:#fff;--shiki-dark-bg:#24292e;color:#24292e;--shiki-dark:#e1e4e8\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">class</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\"> Solution</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> {</span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">public:</span></span>\n<span class=\"line\"><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">    vector</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">&#x3C;</span><span style=\"color:#D73A49;--shiki-dark:#F97583\">int</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">> </span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">closestEqualElementQueries</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">(</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">vector</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">&#x3C;</span><span style=\"color:#D73A49;--shiki-dark:#F97583\">int</span><span style=\"colo

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