Algorithm
Problem Name: 1024. Video Stitching
You are given a series of video clips from a sporting event that lasted time seconds. These video clips can be overlapping with each other and have varying lengths.
Each video clip is described by an array clips where clips[i] = [starti, endi] indicates that the ith clip started at starti and ended at endi.
We can cut these clips into segments freely.
- For example, a clip
[0, 7]can be cut into segments[0, 1] + [1, 3] + [3, 7].
Return the minimum number of clips needed so that we can cut the clips into segments that cover the entire sporting event [0, time]. If the task is impossible, return -1.
Example 1:
Input: clips = [[0,2],[4,6],[8,10],[1,9],[1,5],[5,9]], time = 10 Output: 3 Explanation: We take the clips [0,2], [8,10], [1,9]; a total of 3 clips. Then, we can reconstruct the sporting event as follows: We cut [1,9] into segments [1,2] + [2,8] + [8,9]. Now we have segments [0,2] + [2,8] + [8,10] which cover the sporting event [0, 10].
Example 2:
Input: clips = [[0,1],[1,2]], time = 5 Output: -1 Explanation: We cannot cover [0,5] with only [0,1] and [1,2].
Example 3:
Input: clips = [[0,1],[6,8],[0,2],[5,6],[0,4],[0,3],[6,7],[1,3],[4,7],[1,4],[2,5],[2,6],[3,4],[4,5],[5,7],[6,9]], time = 9 Output: 3 Explanation: We can take clips [0,4], [4,7], and [6,9].
Constraints:
1 <= clips.length <= 1000 <= starti <= endi <= 1001 <= time <= 100
Code Examples
#1 Code Example with Javascript Programming
Code -
Javascript Programming
const videoStitching = function (clips, T) {
clips.sort((a, b) => a[0] - b[0])
if(T === 0) return 0
let laststart = -1,
curend = 0,
count = 0
for (let i = 0; i < clips.length; > {
if (clips[i][0] > curend) return -1
let maxend = curend
// while one clip's start is before or equal to current end
while (i < clips.length && clips[i][0] <= curend) {
maxend = Math.max(maxend, clips[i][1])
i++
}
count++
curend = maxend
if (curend >= T) return count
}
return -1
}
Input
Output
#2 Code Example with Python Programming
Code -
Python Programming
class Solution:
def videoStitching(self, clips: List[List[int]], T: int) -> int:
clips.sort(key = lambda x: (-x[0], x[1]))
x = cnt = mx = 0
while clips and clips[-1][0] <= x < T:
while clips and clips[-1][0] <= x:
mx = max(mx, clips.pop()[1])
if mx > x:
x = mx
cnt += 1
return cnt if x >= T else -1
Input
Output
#3 Code Example with C# Programming
Code -
C# Programming
using System;
namespace LeetCode
{
public class _1024_VideoStitching
{
public int VideoStitching(int[][] clips, int T)
{
Array.Sort(clips, (a, b) => a[0].CompareTo(b[0]));
int count = 0;
int start = 0, end = 0;
for (int i = 0; i < clips.Length && start < T; i++)
{
while (i < clips.Length && clips[i][0] <= start)
end = Math.Max(end, clips[i++][1]);
if (start == end) return -1;
count++;
i--;
start = end;
}
return start >= T ? count : -1;
}
}
}
Input
Output