题解 | #合并区间#

import java.util.*;

/*
 * public class Interval {
 *   int start;
 *   int end;
 *   public Interval(int start, int end) {
 *     this.start = start;
 *     this.end = end;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param intervals Interval类ArrayList 
     * @return Interval类ArrayList
     */
    public ArrayList<Interval> merge (ArrayList<Interval> intervals) {
        // write code here
        if (intervals.size() == 0 || intervals == null) {
            return intervals;
        }
        intervals.sort(new Comparator<Interval>(){
            public int compare(Interval o1, Interval o2){
                if(o1.start != o2.start)
                    return o1.start - o2.start;
                else
                    return o1.end - o2.end;
            }});
        
        for (int i = 0; i < intervals.size()-1; i++) {
            if (intervals.get(i).end >= intervals.get(i+1).start) {
                if (!(intervals.get(i).end >= intervals.get(i+1).end)) {
                    intervals.get(i).end = intervals.get(i+1).end;
                }
                intervals.remove(i+1);
                i--;
            }
        }
        return intervals;
    }
}