class Solution {
public:
bool canAttendMeetings(vector<vector<int>>& intervals) {
if(intervals.empty()) {
return true;
}
sort(intervals.begin(),intervals.end(),[](vector<int>a, vector<int>b){
return a[0] < b[0];
});
for(int i = 0; i < intervals.size() - 1; ++i)
{
if(intervals[i][1] > intervals[i+1][0]) {
return false;
}
}
return true;
}
};