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leetcode/apps/docs/content/(05-decision-space)/intervals/435_non-overlapping-intervals.mdx
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---
title: '435. Non-overlapping Intervals'
description: Given an array of intervals intervals where intervals[i] = [starti, endi], return the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping
icon: dot
topics:
- { name: "Array", slug: "array" }
- { name: "Dynamic Programming", slug: "dynamic-programming" }
- { name: "Greedy", slug: "greedy" }
- { name: "Sorting", slug: "sorting" }
issue: "https://github.com/prdlk/leetcode/issues/183"
companies:
- { name: "Microsoft", period: "Thirty Days", frequency: 57.2 }
- { name: "Google", period: "Thirty Days", frequency: 29 }
- { name: "Grammarly", period: "Three Months", frequency: 100 }
- { name: "Amazon", period: "Three Months", frequency: 28.9 }
- { name: "IBM", period: "Six Months", frequency: 60.1 }
- { name: "Bloomberg", period: "Six Months", frequency: 25.5 }
sidebar:
label: 'Non-overlapping Intervals'
badge: 'Medium'
---
### Example 1:
- Input: `intervals = [[1,2],[2,3],[3,4],[1,3]]`
- Output: `1`
- Explanation: `[1,3]` can be removed and the rest of the `intervals` are non-overlapping.
### Example 2:
- Input: `intervals = [[1,2],[1,2],[1,2]]`
- Output: `2`
- Explanation: You need to remove two `[1,2]` to make the rest of the `intervals` non-overlapping.
### Example 3:
- Input: `intervals = [[1,2],[2,3]]`
- Output: `0`
- Explanation: You don't need to remove any of the `intervals` since they're already non-overlapping.
### Constraints:
- `1 <= intervals.length <= 10^5`
- `intervals[i].length == 2`
- `-5 * 10^4 <= starti < endi <= 5 * 10^4`
## Solution
```py
class Solution:
def eraseOverlapIntervals(self, intervals: list[list[int]]) -> int:
intervals.sort(key=lambda x: x[0])
result = []
for start, end in intervals:
# Use '<' to avoid intervals which touch
if result and start < result[-1][1]:
result[-1][1] = min(result[-1][1], end)
else:
result.append([start, end])
# Difference between original and result is to remove
return len(intervals) - len(result)
```