代码随想训练营第三十六天（Python）｜ 435. 无重叠区间、763.划分字母区间、56. 合并区间

435. 无重叠区间

class Solution:
    def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int:
        intervals.sort(key=lambda x: x[0])
        count = 0
        for i in range(1, len(intervals)):
            if intervals[i][0] < intervals[i-1][1]:
                intervals[i][1] = min(intervals[i-1][1], intervals[i][1])
                count += 1
        return count

763.划分字母区间

class Solution:
    def partitionLabels(self, s: str) -> List[int]:
        end_dict = {}
        # 获取每个字母的最远坐标
        for i, ch in enumerate(s):
            end_dict[ch] = i

        start = 0
        end = 0
        res = []
        for i, ch in enumerate(s):
            # 更新每个字母的最远坐标
            end = max(end, end_dict[ch])
            # 遍历到这个区间的最远坐标，划分区间
            if i == end:
                res.append(end - start + 1)
                start = i + 1
        return res

56. 合并区间

class Solution:
    def merge(self, intervals: List[List[int]]) -> List[List[int]]:
        intervals.sort(key=lambda x: x[0])
        res = []
        res.append(intervals[0])
        for i in range(1, len(intervals)):
            if res[-1][1] >= intervals[i][0]:
                res[-1][1] = max(intervals[i][1], res[-1][1])
            else:
                res.append(intervals[i])    
        return res