Insert Interval

Source

• lintcode: Insert Interval

Given a non-overlapping interval list which is sorted by start point.

Insert a new interval into it, make sure the list is still in order and non-overlapping (merge intervals if necessary).

Example
Insert [2, 5] into [[1,2], [5,9]], we get [[1,9]].

Insert [3, 4] into [[1,2], [5,9]], we get [[1,2], [3,4], [5,9]].

Python

"""
Definition of Interval.
class Interval(object):
    def __init__(self, start, end):
        self.start = start
        self.end = end
"""


class Solution:
    """
    Insert a new interval into a sorted non-overlapping interval list.
    @param intevals: Sorted non-overlapping interval list
    @param newInterval: The new interval.
    @return: A new sorted non-overlapping interval list with the new interval.
    """
    def insert(self, intervals, newInterval):
        result=[]

        pos=0

        for interval in intervals:
            if newInterval.end < interval.start:
                result.append(interval)
            elif interval.end<newInterval.start:
                result.append(interval)
                pos+=1
            else:
                newInterval.start = min(newInterval.start, interval.start)
                newInterval.end = max(newInterval.end, interval.end)

        result.insert(pos, newInterval)
        return result

Java

/**
 * Definition of Interval:
 * public classs Interval {
 *     int start, end;
 *     Interval(int start, int end) {
 *         this.start = start;
 *         this.end = end;
 *     }
 */

class Solution {
    /**
     * Insert newInterval into intervals.
     * @param intervals: Sorted interval list.
     * @param newInterval: A new interval.
     * @return: A new sorted interval list.
     */
    public ArrayList<Interval> insert(ArrayList<Interval> intervals, Interval newInterval) {
        ArrayList<Interval> result = new ArrayList<Interval>();
        if(intervals==null){
            return null;
        }
        int pos=0;

        for(Interval interval: intervals){
            if(newInterval.end<interval.start){
                result.add(interval);
            }
            else if(interval.end< newInterval.start){
                result.add(interval);
                pos++;
            }
            else{
                newInterval.start = Math.min(newInterval.start, interval.start);
                newInterval.end = Math.max(newInterval.end, interval.end);
            }
        }
        result.add(pos, newInterval);
        return result;
    }
}