leetcode : Insert Interval

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary).

You may assume that the intervals were initially sorted according to their start times.

Example 1:

Given intervals [1,3],[6,9], insert and merge [2,5] in as [1,5],[6,9].

Example 2:

Given [1,2],[3,5],[6,7],[8,10],[12,16], insert and merge [4,9] in as [1,2],[3,10],[12,16].

This is because the new interval [4,9] overlaps with [3,5],[6,7],[8,10].

 

 

 

tag: 对象排序， List转换成数组

 

/**
 * Definition for an interval.
 * public class Interval {
 *     int start;
 *     int end;
 *     Interval() { start = 0; end = 0; }
 *     Interval(int s, int e) { start = s; end = e; }
 * }
 */
public class Solution {
    public List<Interval> insert(List<Interval> intervals, Interval newInterval) {
        
        List<Interval> result = new ArrayList<Interval>();
        intervals.add(newInterval);
        if(intervals == null || intervals.size() == 0) {
            return result;
        }
        
        int size = intervals.size();
        
        Interval[] intervalArr = intervals.toArray(new Interval[size]);
        Arrays.sort(intervalArr, new Comparator<Interval>(){
            public int compare(Interval interval1, Interval interval2) {
                return interval1.start - interval2.start;
            }
        });
        Interval mover = intervalArr[0];
        for(int i = 1; i < size; i++) {
            if(mover.end < intervalArr[i].start) {
                result.add(mover);
                mover = intervalArr[i];
            } else {
                mover.end = Math.max(mover.end, intervalArr[i].end);
            }
        }
        result.add(mover);
        
        return result;
        
    }
}