给定两个日期范围,确定两个日期是否重叠的最简单或最有效的方法是什么?

例如,假设我们有由DateTime变量StartDate1到EndDate1和StartDate2到EndDate2表示的范围。


当前回答

为了涵盖PHP/LaravelCarbon包中的所有重叠情况,您可以在Charles的答案中展开逻辑,如下所示。

if ( ($startTime1->between($startTime2, $endTime2, true) || $endTime1->between($startTime2, $endTime2, true)) || (($startTime1 <= $endTime2) && ($endTime2 <= $endTime1)) ){
//Complete Overlap, Partial Left Overlap, Partial Right Overlap. 
}

这将检查StartTime1是否在(StartTime2-EndTime2)范围之间,或者EndTime1是否位于(StartTime2-EndTime2的范围之间。

其余部分完全重叠,如其他答案所述。

其他回答

这里还有一个使用JavaScript的解决方案。我的解决方案的特点:

将空值处理为无穷大假设下限是包含的,上限是不包含的。附带一系列测试

这些测试基于整数,但由于JavaScript中的日期对象是可比较的,因此您也可以添加两个日期对象。或者您可以输入毫秒时间戳。

代码:

/**
 * Compares to comparable objects to find out whether they overlap.
 * It is assumed that the interval is in the format [from,to) (read: from is inclusive, to is exclusive).
 * A null value is interpreted as infinity
 */
function intervalsOverlap(from1, to1, from2, to2) {
    return (to2 === null || from1 < to2) && (to1 === null || to1 > from2);
}

测验:

describe('', function() {
    function generateTest(firstRange, secondRange, expected) {
        it(JSON.stringify(firstRange) + ' and ' + JSON.stringify(secondRange), function() {
            expect(intervalsOverlap(firstRange[0], firstRange[1], secondRange[0], secondRange[1])).toBe(expected);
        });
    }

    describe('no overlap (touching ends)', function() {
        generateTest([10,20], [20,30], false);
        generateTest([20,30], [10,20], false);

        generateTest([10,20], [20,null], false);
        generateTest([20,null], [10,20], false);

        generateTest([null,20], [20,30], false);
        generateTest([20,30], [null,20], false);
    });

    describe('do overlap (one end overlaps)', function() {
        generateTest([10,20], [19,30], true);
        generateTest([19,30], [10,20], true);

        generateTest([10,20], [null,30], true);
        generateTest([10,20], [19,null], true);
        generateTest([null,30], [10,20], true);
        generateTest([19,null], [10,20], true);
    });

    describe('do overlap (one range included in other range)', function() {
        generateTest([10,40], [20,30], true);
        generateTest([20,30], [10,40], true);

        generateTest([10,40], [null,null], true);
        generateTest([null,null], [10,40], true);
    });

    describe('do overlap (both ranges equal)', function() {
        generateTest([10,20], [10,20], true);

        generateTest([null,20], [null,20], true);
        generateTest([10,null], [10,null], true);
        generateTest([null,null], [null,null], true);
    });
});

使用karma&jasmine&PhantomJS运行时的结果:

PhantomJS 1.9.8(Linux):执行20次成功(0.003秒/0.004秒)

在Microsoft SQL SERVER中-SQL函数

CREATE FUNCTION IsOverlapDates 
(
    @startDate1 as datetime,
    @endDate1 as datetime,
    @startDate2 as datetime,
    @endDate2 as datetime
)
RETURNS int
AS
BEGIN
DECLARE @Overlap as int
SET @Overlap = (SELECT CASE WHEN  (
        (@startDate1 BETWEEN @startDate2 AND @endDate2) -- caters for inner and end date outer
        OR
        (@endDate1 BETWEEN @startDate2 AND @endDate2) -- caters for inner and start date outer
        OR
        (@startDate2 BETWEEN @startDate1 AND @endDate1) -- only one needed for outer range where dates are inside.
        ) THEN 1 ELSE 0 END
    )
    RETURN @Overlap

END
GO

--Execution of the above code
DECLARE @startDate1 as datetime
DECLARE @endDate1 as datetime
DECLARE @startDate2 as datetime
DECLARE @endDate2 as datetime
DECLARE @Overlap as int
SET @startDate1 = '2014-06-01 01:00:00' 
SET @endDate1 =   '2014-06-01 02:00:00'
SET @startDate2 = '2014-06-01 01:00:00' 
SET @endDate2 =   '2014-06-01 01:30:00'

SET @Overlap = [dbo].[IsOverlapDates]  (@startDate1, @endDate1, @startDate2, @endDate2)

SELECT Overlap = @Overlap

这是我的Java解决方案,它也适用于无限区间

private Boolean overlap (Timestamp startA, Timestamp endA,
                         Timestamp startB, Timestamp endB)
{
    return (endB == null || startA == null || !startA.after(endB))
        && (endA == null || startB == null || !endA.before(startB));
}

只要有简单的解决方案,仅仅使用额外的包来做简单的事情可能效率不高。但是,如果您已经在项目中使用了日期fns,那么有一个名为areIntervalsOverlapping的方法也会执行同样的操作。

语法:

areIntervalsOverlapping(intervalLeft, intervalRight, [options])

例子:

// For overlapping time intervals:
areIntervalsOverlapping(
  { start: new Date(2014, 0, 10), end: new Date(2014, 0, 20) },
  { start: new Date(2014, 0, 17), end: new Date(2014, 0, 21) }
)
//=> true

我认为,在以下情况下,两个范围重叠就足够了:

(StartDate1 <= EndDate2) and (StartDate2 <= EndDate1)