From cd4d54616200a53d9a22fbd919edf905ad1d4dd1 Mon Sep 17 00:00:00 2001 From: jianghongcheng <35664721+jianghongcheng@users.noreply.github.com> Date: Thu, 1 Jun 2023 02:16:29 -0500 Subject: [PATCH] =?UTF-8?q?Update=200435.=E6=97=A0=E9=87=8D=E5=8F=A0?= =?UTF-8?q?=E5=8C=BA=E9=97=B4.md?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- problems/0435.无重叠区间.md | 41 +++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 8 deletions(-) diff --git a/problems/0435.无重叠区间.md b/problems/0435.无重叠区间.md index 37ef819d..61f42d42 100644 --- a/problems/0435.无重叠区间.md +++ b/problems/0435.无重叠区间.md @@ -248,20 +248,45 @@ class Solution { ``` ### Python +贪心 基于左边界 ```python class Solution: def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int: - if len(intervals) == 0: return 0 - intervals.sort(key=lambda x: x[1]) - count = 1 # 记录非交叉区间的个数 - end = intervals[0][1] # 记录区间分割点 + if not intervals: + return 0 + + intervals.sort(key=lambda x: x[0]) # 按照左边界升序排序 + count = 0 # 记录重叠区间数量 + for i in range(1, len(intervals)): - if end <= intervals[i][0]: + if intervals[i][0] < intervals[i - 1][1]: # 存在重叠区间 + intervals[i][1] = min(intervals[i - 1][1], intervals[i][1]) # 更新重叠区间的右边界 count += 1 - end = intervals[i][1] - return len(intervals) - count -``` + + return count +``` +贪心 基于左边界 把452.用最少数量的箭引爆气球代码稍做修改 +```python +class Solution: + def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int: + if not intervals: + return 0 + + intervals.sort(key=lambda x: x[0]) # 按照左边界升序排序 + + result = 1 # 不重叠区间数量,初始化为1,因为至少有一个不重叠的区间 + + for i in range(1, len(intervals)): + if intervals[i][0] >= intervals[i - 1][1]: # 没有重叠 + result += 1 + else: # 重叠情况 + intervals[i][1] = min(intervals[i - 1][1], intervals[i][1]) # 更新重叠区间的右边界 + + return len(intervals) - result + + +``` ### Go ```go func eraseOverlapIntervals(intervals [][]int) int {