Leetcode-Insert Interval

LiBlog發表於2014-11-14

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].

Solution:

 1 /**
 2  * Definition for an interval.
 3  * public class Interval {
 4  *     int start;
 5  *     int end;
 6  *     Interval() { start = 0; end = 0; }
 7  *     Interval(int s, int e) { start = s; end = e; }
 8  * }
 9  */
10 public class Solution {
11     public List<Interval> insert(List<Interval> intervals, Interval newInterval) {
12         List<Interval> result = new ArrayList<Interval>();
13         if (intervals.size()==0){
14             result.add(newInterval);
15             return result;
16         }
17         
18         int next = 0;
19         while (next<intervals.size() && intervals.get(next).end < newInterval.start){
20             result.add(intervals.get(next));
21             next++;
22         }
23         
24         while (next<intervals.size() && intervals.get(next).start <= newInterval.end){
25             newInterval.start = Math.min(intervals.get(next).start,newInterval.start);
26             newInterval.end = Math.max(intervals.get(next).end,newInterval.end);
27             next++;
28         }
29         
30         result.add(newInterval);
31         
32         while (next<intervals.size()){
33             result.add(intervals.get(next));
34             next++;
35         }
36         
37         return result;
38     }
39 }

 

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