Merge Intervals

 idea: sort by the first dimension and then do it in a natural way.


bool operator<(const Interval &v1, const Interval &v2) { return v1.start < v2.start; }
class Solution {
public:

vector<Interval> merge(vector<Interval> &intervals) {
    vector<Interval> cc;
    sort(intervals.begin(), intervals.end());
    int n = intervals.size();
    int i = 0;
    while(i < n) {
        cc.push_back(intervals[i++]);
        while(i < n && intervals[i].start <= cc.back().end)
            cc.back().end = max(cc.back().end, intervals[i++].end);
    }
    return cc;
}