56 Merge Intervals
Problem:
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].
Solutions:
/**
* 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> merge(List<Interval> intervals) {
Collections.sort(intervals, new Comparator<Interval>(){
public int compare(Interval i1, Interval i2) {
if (i1.start != i2.start) {
return i1.start - i2.start;
}
else {
return i1.end - i2.end;
}
}
});
List<Interval> result = new LinkedList<Interval>();
Interval curr = null;
for (Interval inter:intervals) {
if (curr == null) {
curr = inter;
continue;
}
if (inter.start > curr.end) {
result.add(curr);
curr = inter;
}
else {
curr.end = Math.max(curr.end, inter.end);
}
}
if (curr != null) {
result.add(curr);
}
return result;
}
}