<p>You are given an integer array <code>nums</code> and two integers <code>indexDiff</code> and <code>valueDiff</code>.</p>

<p>Find a pair of indices <code>(i, j)</code> such that:</p>

<ul>
	<li><code>i != j</code>,</li>
	<li><code>abs(i - j) &lt;= indexDiff</code>.</li>
	<li><code>abs(nums[i] - nums[j]) &lt;= valueDiff</code>, and</li>
</ul>

<p>Return <code>true</code><em> if such pair exists or </em><code>false</code><em> otherwise</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3,1], indexDiff = 3, valueDiff = 0
<strong>Output:</strong> true
<strong>Explanation:</strong> We can choose (i, j) = (0, 3).
We satisfy the three conditions:
i != j --&gt; 0 != 3
abs(i - j) &lt;= indexDiff --&gt; abs(0 - 3) &lt;= 3
abs(nums[i] - nums[j]) &lt;= valueDiff --&gt; abs(1 - 1) &lt;= 0
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,5,9,1,5,9], indexDiff = 2, valueDiff = 3
<strong>Output:</strong> false
<strong>Explanation:</strong> After trying all the possible pairs (i, j), we cannot satisfy the three conditions, so we return false.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>2 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>9</sup> &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
	<li><code>1 &lt;= indexDiff &lt;= nums.length</code></li>
	<li><code>0 &lt;= valueDiff &lt;= 10<sup>9</sup></code></li>
</ul>

class Solution {
public:
    bool containsNearbyAlmostDuplicate(vector<int>& nums, int indexDiff, int valueDiff) {
        int n = nums.size();
        vector<pair<int,int>> maps;
        maps.reserve(n);
        for (int i = 0; i < n; ++i) maps.push_back(make_pair(nums[i],i));
        
        std::sort(maps.begin(), maps.end());
        
        // std::cout << "printing ordered" << std::endl;
        // for (pair<int,int>& p : maps) {
        //     std::cout << p.first << ", " << p.second << '\t';
        // }
        // std::cout << std::endl;
        
        set<int> active = {maps.front().second};
        int beg = 0, end = 1;
        while (end < n) {
            if (maps[end].first - maps[beg].first <= valueDiff) {
                auto first_after = active.lower_bound(maps[end].second);
                // std::cout << "first_after was " << *first_after << " and then became " << *(--first_after)  << std::endl;
                first_after = active.lower_bound(maps[end].second);
                if (first_after!=active.end() && (abs(*first_after-maps[end].second) <= indexDiff)) return true;
                if (first_after!=active.begin()) {                
                    --first_after;
                    if (abs(*first_after-maps[end].second) <= indexDiff) return true;
                }
                
                active.insert(maps[end].second);
                // std::cout << "just inserted " << maps[end].second << " to our set" << std::endl;
                end++;
            } else {
                active.erase(maps[beg].second);
                // std::cout << "just erased " << maps[beg].second << " from our set" << std::endl;
                beg++;
                // end = max(beg+1, end);
            }
        }
        return false;
    }
};
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