<p>You are given an array of <code>intervals</code>, where <code>intervals[i] = [start<sub>i</sub>, end<sub>i</sub>]</code> and each <code>start<sub>i</sub></code> is <strong>unique</strong>.</p>

<p>The <strong>right interval</strong> for an interval <code>i</code> is an interval <code>j</code> such that <code>start<sub>j</sub> &gt;= end<sub>i</sub></code> and <code>start<sub>j</sub></code> is <strong>minimized</strong>. Note that <code>i</code> may equal <code>j</code>.</p>

<p>Return <em>an array of <strong>right interval</strong> indices for each interval <code>i</code></em>. If no <strong>right interval</strong> exists for interval <code>i</code>, then put <code>-1</code> at index <code>i</code>.</p>

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

<pre>
<strong>Input:</strong> intervals = [[1,2]]
<strong>Output:</strong> [-1]
<strong>Explanation:</strong> There is only one interval in the collection, so it outputs -1.
</pre>

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

<pre>
<strong>Input:</strong> intervals = [[3,4],[2,3],[1,2]]
<strong>Output:</strong> [-1,0,1]
<strong>Explanation:</strong> There is no right interval for [3,4].
The right interval for [2,3] is [3,4] since start<sub>0</sub> = 3 is the smallest start that is &gt;= end<sub>1</sub> = 3.
The right interval for [1,2] is [2,3] since start<sub>1</sub> = 2 is the smallest start that is &gt;= end<sub>2</sub> = 2.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> intervals = [[1,4],[2,3],[3,4]]
<strong>Output:</strong> [-1,2,-1]
<strong>Explanation:</strong> There is no right interval for [1,4] and [3,4].
The right interval for [2,3] is [3,4] since start<sub>2</sub> = 3 is the smallest start that is &gt;= end<sub>1</sub> = 3.
</pre>

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

<ul>
	<li><code>1 &lt;= intervals.length &lt;= 2 * 10<sup>4</sup></code></li>
	<li><code>intervals[i].length == 2</code></li>
	<li><code>-10<sup>6</sup> &lt;= start<sub>i</sub> &lt;= end<sub>i</sub> &lt;= 10<sup>6</sup></code></li>
	<li>The start point of each interval is <strong>unique</strong>.</li>
</ul>

class Solution {
public:
    template<typename T, typename F>
    pair<T, T> search(T l, T r, F cond) {
        if (cond(l) == false) return {l - 1, l};
        if (cond(r) == true) return {r, r + 1};
        while (l + 1 < r) {
            auto m = l + (r - l) / 2;
            if (cond(m)) l = m;
            else r = m;
        }
        return {l, r};
    }

    vector<int> findRightInterval(vector<vector<int>>& intervals) {
        int n = intervals.size();
        vector<vector<int>> sorted;
        for (int i = 0; i < n; ++i) {
            sorted.emplace_back(intervals[i]);
            sorted.back().emplace_back(i); // save index for ref
        }
        sort(sorted.begin(), sorted.end());

        vector<int> res;
        for (int i = 0; i < n; ++i) { // x <= target, check right bound
            auto target = intervals[i][1];
            auto [l, r] = search(0, n - 1, [&](int idx) {
                return !(sorted[idx][0] >= target);
            });
            if (r >= n) res.emplace_back(-1);
            else res.emplace_back(sorted[r][2]);
        }
        return res;
    }
};
36288