0057. Insert Interval

https://leetcode.com/problems/insert-interval

Description

You are given an array of non-overlapping intervals intervals where intervals[i] = [starti, endi] represent the start and the end of the ith interval and intervals is sorted in ascending order by starti. You are also given an interval newInterval = [start, end] that represents the start and end of another interval.

Insert newInterval into intervals such that intervals is still sorted in ascending order by starti and intervals still does not have any overlapping intervals (merge overlapping intervals if necessary).

Return intervals after the insertion.

Example 1:

**Input:** intervals = [[1,3],[6,9]], newInterval = [2,5]
**Output:** [[1,5],[6,9]]

Example 2:

**Input:** intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
**Output:** [[1,2],[3,10],[12,16]]
**Explanation:** Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10].

Example 3:

**Input:** intervals = [], newInterval = [5,7]
**Output:** [[5,7]]

Example 4:

**Input:** intervals = [[1,5]], newInterval = [2,3]
**Output:** [[1,5]]

Example 5:

**Input:** intervals = [[1,5]], newInterval = [2,7]
**Output:** [[1,7]]

Constraints:

• 0 <= intervals.length <= 104

• intervals[i].length == 2

• 0 <= starti <= endi <= 105

• intervals is sorted by starti in ascending order.

• newInterval.length == 2

• 0 <= start <= end <= 105

ac

/**
 * 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; }
 * }
 */
class Solution {
    public List<Interval> insert(List<Interval> intervals, Interval newInterval) {
        List<Interval> res = new ArrayList<Interval>();
        // edge cases
        if (intervals == null || newInterval == null) return res;

        // iterate list
        int start = newInterval.start, end = newInterval.end;
        int i = 0;
        for (; i < intervals.size(); i++) {
            Interval curr = intervals.get(i);
            if (curr.end < start) {  // won't cover this interval, skip
                res.add(curr);
            } else if (curr.start > end) {  // merge complete
                break;
            } else {
                start = Math.min(start, curr.start);
                end = Math.max(end, curr.end);
            }
        }
        // new interval
        Interval insert = new Interval(start, end);
        res.add(insert);
        // add remaining
        for (; i < intervals.size(); i++) {  
            res.add(intervals.get(i));
        }

        return res;
    }
}