snippets

#include <algorithm>
#include <vector>

std::vector<std::vector<int>> merge(std::vector<std::vector<int>>& intervals) {
    std::sort(intervals.begin(), intervals.end());
    std::vector<std::vector<int>> res;
    for (auto& iv : intervals) {
        if (!res.empty() && iv[0] <= res.back()[1])
            res.back()[1] = std::max(res.back()[1], iv[1]);
        else
            res.push_back(iv);
    }
    return res;
}