以数组 intervals 表示若干个区间的集合,其中单个区间为 intervals[i] = [starti, endi] 。请你合并所有重叠的区间,并返回一个不重叠的区间数组,该数组需恰好覆盖输入中的所有区间
https://leetcode-cn.com/problems/merge-intervals/
示例1:
示例2:
提示:
Java解法
package sj.shimmer.algorithm.m2;
import java.util.ArrayList;
import java.util.List;
/**
* Created by SJ on 2021/2/27.
*/
class D34 {
public static void main(String[] args) {
int[][] merge = merge(new int[][]{{1, 3}, {2, 6}, {8, 10}, {15, 18}});
int[][] merge1 = merge(new int[][]{{1, 4}, {4, 5}});
int[][] merge2 = merge(new int[][]{{2,3},{2,2},{3,3},{1,3},{5,7},{2,2},{4,6}});
for (int[] ints : merge2) {
for (int anInt : ints) {
System.out.print(anInt);
System.out.print(",");
}
System.out.println("---");
}
}
public static int[][] merge(int[][] intervals) {
List<int[]> list = new ArrayList<>();
for (int[] interval : intervals) {
list.add(interval);
}
List<int[]> merge = merge(list, 0);
return merge.toArray(new int[merge.size()][2]);
}
public static List<int[]> merge(List<int[]> lists,int index) {
if (lists != null&&lists.size()>index) {
int[] compare = lists.get(index);
for (int i = index+1; i < lists.size(); i++) {
int[] interval = lists.get(i);
//无重叠情况
if (interval[0]>compare[1]||interval[1]<compare[0]) {
if (i==lists.size()-1) {
return merge(lists,++index);
}
continue;
}else {
compare[0]=Math.min(interval[0],compare[0]);
compare[1]=Math.max(interval[1],compare[1]);
lists.remove(interval);
return merge(lists,index);
}
}
}
return lists;
}
}
官方解
https://leetcode-cn.com/problems/merge-intervals/solution/he-bing-qu-jian-by-leetcode-solution/
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排序
时间复杂度:O(n log n)
空间复杂度:O(log n)