如何为JAVA编写简单的主函数

Question

I am a beginner to JAVA. I am doing the problem "insert intervals" in LeetCode. Below is the problem.

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary).

Example 1: Given intervals [1,3],[6,9], insert and merge [2,5] in as [1,5],[6,9]."

Below is the code. But I don't know how to write a main function. Anyone can help? Thank you very much!

public class Solution {
public List<Interval> insert(List<Interval> intervals, Interval newInterval) {
    List<Interval> res = new ArrayList<Interval>();
    boolean inserted = false;
    for (Interval it : intervals) {
        if (inserted || it.end < newInterval.start) {
            res.add(it);
        } else if (it.start > newInterval.end) {
            res.add(newInterval);
            res.add(it);
            inserted = true;
        } else {
            newInterval.start = Math.min(newInterval.start, it.start);
            newInterval.end = Math.max(newInterval.end, it.end);
        }
    }
    if (inserted == false) res.add(newInterval);
    return res;

public static void main(String[] args) {

    }
}

Answer 1

Assuming you just want to test the written method, this should help.

public static void main(String[] args) {
    Solution solution = new Solution();
    List<Interval> intervals = new ArrayList<>(); //Create list of intervals
    intervals.add(new Interval(1, 3));
    intervals.add(new Interval(6, 9));
    List<Interval> mergedIntervals = solution.insert(intervals, new Interval(2, 5));
    System.out.println(mergedIntervals);
}

I hope the above code is self-explanatory. I think you already have the class Interval defined. This is how it could look

private class Interval {
    int start;
    int end;
    public Interval(int start, int end) {
        this.start = start;
        this.end = end;
    }

    @Override
    public String toString() {
        return "[" + start + "," + end + "]";
    }
}