【LeetCode】 57. Insert Interval 插入区间(Hard)(JAVA)

【LeetCode】 57. Insert Interval 插入区间(Hard)(JAVA)

题目地址: https://leetcode.com/problems/insert-interval/

题目描述:

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

You may assume that the intervals were initially sorted according to their start times.

Example 1:

Input: intervals = [[1,3],[6,9]], newInterval = [2,5]
Output: [[1,5],[6,9]]

Example 2:

Input: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
Output: [[1,2],[3,10],[12,16]]
Explanation: Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10].

NOTE: input types have been changed on April 15, 2019. Please reset to default code definition to get new method signature.

题目大意

给出一个无重叠的 ,按照区间起始端点排序的区间列表。

在列表中插入一个新的区间,你需要确保列表中的区间仍然有序且不重叠(如果有必要的话,可以合并区间)。

解题方法

newInterval 和 intervals[i] 存在三种情况,分别做处理即可
1、newInterval 完全大于 intervals[i]:intervals[len] = intervals[i]
2、newInterval 完全小于 intervals[i]:intervals[len] = newInterval, intervals[i] 为新的 newInterval
3、newInterval 与 intervals[i] 有交集:newInterval 为 newInterval 与 intervals[i] 的并集

class Solution {
    public int[][] insert(int[][] intervals, int[] newInterval) {
        int len = 0;
        for (int i = 0; i < intervals.length; i++) {
            if (intervals[i][0] > newInterval[1]) {
                int[] temp = newInterval;
                newInterval = intervals[i];
                intervals[len] = temp;
                len++;
            } else if (intervals[i][1] < newInterval[0]) {
                swap(intervals, len, i);
                len++;
            } else {
                newInterval[0] = Math.min(intervals[i][0], newInterval[0]);
                newInterval[1] = Math.max(intervals[i][1], newInterval[1]);
            }
        }
        int[][] res = new int[len + 1][2];
        for (int  i = 0; i < len; i++) {
            res[i] = intervals[i];
        }
        res[len] = newInterval;
        return res;
    }

    public void swap(int[][] intervals, int i, int j) {
        if (i == j || i >= intervals.length || j >= intervals.length) return;
        int[] temp = intervals[i];
        intervals[i] = intervals[j];
        intervals[j] = temp;
    }
}

执行用时 : 1 ms, 在所有 Java 提交中击败了 99.73% 的用户
内存消耗 : 41.9 MB , 在所有 Java 提交中击败了 31.21% 的用户

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转载自blog.csdn.net/qq_16927853/article/details/104782722