Leetcode 57. Insert Interval

Insert Interval

• Total accepted:64309
• Total submissions:260619
• Difficulty:hard

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary).

Assume that the intervals were initially sorted according to their start times.

Example 1:
Given intervals [1,3],[6,9] , insert and merge in as [2,5] [1,5],[6,9] .

Example 2:
Given [1,2],[3,5],[6,7],[8,10],[12,16] , insert and merge in as [4,9] [1,2],[3,10],[12,16] .

This is because, the new interval [4,9] overlaps with [3,5],[6,7],[8,10] .

Idea: Interval division. The left boundary of the new interval is found, and the right boundary of the new interval is found. Drawing will be clearer.

Left boundary: Not satisfying intervals[i].end<newinterval.start means intervals[i-1].end<newinterval.start<=intervals[i].end.

Right boundary: When Intervals[j].start<newinterval.end is satisfied, the interval is merged, Intervals[j] and NewInterval are merged into New NewInterval, and then try and intervals[j+ 1] Merge until it cannot be merged. Because Intervals[j] and intervals[j+1] are interval Independent, intervals[j] merging does not affect intervals[j+1].

Code:

1 /**2 * Definition for an interval.3 * struct 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  */Ten classSolution { One  Public: Avector<interval> Insert (vector<interval>&intervals, Interval newinterval) { -         inti,j; -Vector<interval>Res; the          for(i=0; I<intervals.size () &&intervals[i].end<newinterval.start;i++) {//I - Res.push_back (Intervals[i]); -         } -          for(J=i;j<intervals.size () &&intervals[j].start<=newinterval.end;j++){ +Newinterval=Interval (min (Intervals[j].start,newinterval.start), Max (intervals[j].end,newinterval.end)); -         } + Res.push_back (newinterval); A          for(; J<intervals.size (); j + +){ at Res.push_back (Intervals[j]); -         } -         returnRes; -     } -};

Leetcode 57. Insert Interval