leetcode Insert Interval

class Solution {
public:
vector<Interval> insert(vector<Interval> &intervals, Interval newInterval) {

vector<Interval> res;
int size = intervals.size();

int i;
for(i = 0; i<size && intervals[i].end<newInterval.start; ++i)
res.push_back(intervals[i]);

if(i<size)
newInterval.start = min(newInterval.start, intervals[i].start);

for(; i < size && newInterval.end>=intervals[i].start; ++i)
if(newInterval.end<intervals[i].end)
newInterval.end = intervals[i].end;

res.push_back(newInterval);

res.insert(res.end(), intervals.begin()+i, intervals.end());

return res;
}

};