Created
December 20, 2012 23:06
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Given a collection of intervals, merge all overlapping intervals. For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18].
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/** | |
* 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; } | |
* } | |
*/ | |
import java.util.*; | |
public class Solution { | |
public ArrayList<Interval> merge(ArrayList<Interval> intervals) { | |
// Start typing your Java solution below | |
// DO NOT write main() function | |
if(intervals.size() == 0) | |
return intervals; | |
if(intervals.size() == 1) | |
return intervals; | |
Collections.sort(intervals, new IntervalComparator()); | |
Interval first = intervals.get(0); | |
int start = first.start; | |
int end = first.end; | |
ArrayList<Interval> result = new ArrayList<Interval>(); | |
for(int i = 1; i < intervals.size(); i++){ | |
Interval current = intervals.get(i); | |
if(current.start <= end){ | |
end = Math.max(current.end, end); | |
}else{ | |
result.add(new Interval(start, end)); | |
start = current.start; | |
end = current.end; | |
} | |
} | |
result.add(new Interval(start, end)); | |
return result; | |
} | |
} | |
class IntervalComparator implements Comparator{ | |
public int compare(Object o1, Object o2){ | |
Interval i1 = (Interval)o1; | |
Interval i2 = (Interval)o2; | |
return i1.start - i2.start; | |
} | |
} |
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