[LeetCode]Merge Intervals

struct Interval {
int start;
int end;
Interval() : start(0), end(0) {}
Interval(int s, int e) : start(s), end(e) {}
};

class Solution {
//first sort and then merge, O(nlogn)
public:
struct comp
{
bool operator()(const Interval& lhs, const Interval& rhs) const
{
if(lhs.start != rhs.start) return lhs.start < rhs.start;
else return lhs.end < rhs.end;
}
};
vector<Interval> merge(vector<Interval> &intervals) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
if(intervals.size() == 0) return vector<Interval>();
sort(intervals.begin(), intervals.end(), comp());
vector<Interval> ans;
Interval tmp = intervals[0];
for (int i = 1; i < intervals.size(); ++i)
{
if(intervals[i].start <= tmp.end)
tmp.end = max(tmp.end, intervals[i].end);
else
{
ans.push_back(tmp);
tmp = intervals[i];
}
}
ans.push_back(tmp);
return ans;
}
};

/**
* Definition for an interval.
* struct Interval {
*     int start;
*     int end;
*     Interval() : start(0), end(0) {}
*     Interval(int s, int e) : start(s), end(e) {}
* };
*/
class Solution {
public:
struct cmp
{
bool operator()(const Interval& a, const Interval& b)const
{
if(a.start == b.start) return a.end < b.end;
else return a.start < b.start;
}
};

vector<Interval> merge(vector<Interval> &intervals) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
sort(intervals.begin(), intervals.end(), cmp());
vector<Interval> newIntervals;
for(int i = 0; i < intervals.size();)
{
int newEnd = intervals[i].end;
int j;
for(j = i; j < intervals.size(); ++j)
{
if(intervals[j].start <= newEnd) newEnd = max(newEnd, intervals[j].end);
else break;
}
newIntervals.push_back(Interval(intervals[i].start, newEnd));
i = j;
}

return newIntervals;
}
};