# Leetcode - Interval List Intersections

violet posted @ Mar 24, 2020 01:15:03 AM in 算法 with tags Algorithm array Golang , 45 阅读

https://leetcode.com/problems/interval-list-intersections/

Given two lists of closed intervals, each list of intervals is pairwise disjoint and in sorted order.

Return the intersection of these two interval lists.

(Formally, a closed interval `[a, b]` (with `a <= b`) denotes the set of real numbers `x` with `a <= x <= b`.  The intersection of two closed intervals is a set of real numbers that is either empty, or can be represented as a closed interval.  For example, the intersection of [1, 3] and [2, 4] is [2, 3].)

```Input: A = [[0,2],[5,10],[13,23],[24,25]], B = [[1,5],[8,12],[15,24],[25,26]]
Output: [[1,2],[5,5],[8,10],[15,23],[24,24],[25,25]]
Reminder: The inputs and the desired output are lists of Interval objects, and not arrays or lists.```

```func intervalIntersection(A [][]int, B [][]int) [][]int {
result := [][]int{}
i := 0
j := 0
for i < len(A) && j < len(B) {
if isIntersected(A[i], B[j]) {
start := max(A[i][0], B[j][0])
end := min(A[i][1], B[j][1])
result = append(result, []int{start, end})
if A[i][1] < B[j][1] {
i++
} else {
j++
}
} else {
if A[i][1] < B[j][0] {
i++
} else {
if B[j][1] < A[i][0] {
j++
}
}
}
}
return result
}

func isIntersected(a, b []int) bool {
// fmt.Println("a, b: ", a, b)
if a[1] < b[0] || a[0] > b[1] {
return false
}
return true
}

func min(a, b int) int {
if a < b {
return a
}
return b
}

func max(a, b int) int{
if a > b {
return a
}
return b
}```

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