数据结构：数组、列表等

56. Merge Intervals

https://leetcode.com/problems/merge-intervals/

• python

class Solution:
    def merge(self, intervals: List[List[int]]) -> List[List[int]]:
        intervals.sort(key=lambda x:x[0])
        i=0
        while i<len(intervals)-1:
            if intervals[i][1]>=intervals[i+1][0]:
                intervals[i][1]=max(intervals[i+1][1],intervals[i][1])
                del intervals[i+1]
            else:
                i+=1
        return intervals

• java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        int[][] ans=new Solution().merge(new int[][]{{1,3},{2,6},{8,10},{15,18}});
        for(int[] row:ans){
            for (int ele:row){
                System.out.print(ele+" ");
            }
            System.out.println();
        }
    }
}


class Solution {
    Integer[][] toIntegers(int [][] a){  //todo: simplify
        Integer[][] ret=new Integer[a.length][a[0].length];
        for (int i = 0; i <a.length ; i++) {
            for (int j = 0; j < a[0].length; j++) {
                ret[i][j]=a[i][j];
            }
        }
        return ret;
    }
    int[][] toInts(List<Integer[]>  a){  // todo: simplify
        int[][] ret=new int[a.size()][a.get(0).length];
        for (int i = 0; i <a.size() ; i++) {
            for (int j = 0; j < a.get(0).length; j++) {
                ret[i][j]=a.get(i)[j];
            }
        }
        return ret;
    }
    public int[][] merge(int[][] intervals) {
        if(intervals.length==0)
            return new int[][]{};
        Arrays.sort(intervals, Comparator.comparing(e->e[0]));
        // todo: simplify
        List<Integer[]> list=Arrays.asList(toIntegers(intervals)); //代码简化：https://blog.csdn.net/Sun_nowU/article/details/90374481
        List<Integer[]> arrayList=new ArrayList(list);
        int i=0;
        while (i<arrayList.size()-1){
            if(arrayList.get(i)[1]>=arrayList.get(i+1)[0]){
                arrayList.set(i,new Integer[]{arrayList.get(i)[0],
                        Math.max(arrayList.get(i)[1],arrayList.get(i+1)[1])});
                arrayList.remove(i+1);
            }else {
                i++;
            }
        }
        // todo: simplify
        return toInts(arrayList);
    }
}