swift - 识别范围重叠

Question

我有一本描述一个人的名字、出生日期和死亡日期的字典。

var people = [ "Michael": [ "birth": 1900, "death" : 1975 ], "John": [ "birth": 1973, "death" : 2000 ], "Julian": [ "birth": 1950, "death" : 1985 ] ]

我想确定所有成员同时还活着的年份。

这是我相当粗暴且不可扩展的实现:

var years = [Int]()
var overlap = [Int]()    
var overlapTwice = [Int]()
var overlapThree = [Int]()

for life in people.values {
    var birth = Int(life["birth"]!)
    var death = Int(life["death"]!)

    for year in birth..<death {
        if !years.contains(year) {
            years.append(year)
        } else {
            overlap.append(year)
        }
    }
}

for x in overlap {
    if !overlapTwice.contains(x) {
        overlapTwice.append(x)
    } else {
        overlapThree.append(x)
    }
}
print(overlapThree)

我想知道解决这个问题的正确方法，因为我显然需要为每个额外的范围编写一个循环

Answer 1

有一种更简单的方法可以解决这个问题。做一个循环。跟踪最大出生年份和最小死亡年份。那将是你的范围。

如果最大出生数最终大于最小死亡数，则没有重叠。

由于我对 Swift 不是很流利，因此以下内容主要是作为伪代码编写的:

var maxBirth = 0 // start with small value
bar minDeath = 9999 // start with large value
for life in people.values {
    var birth = Int(life["birth"]!)
    var death = Int(life["death"]!)

    if birth > maxBirth {
        maxBirth = birth
    }
    if death < minDeath {
        minDeath = death
    }
}

您的重叠范围将从 maxBirth 到 minDeath。