completed 2248 - intersecton of multiple arrays in go

Author: jgndev

go/intersectionOfMultipleArrays/README.md

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+# 2248. Intersecton of Multiple Arrays
+
+Given a 2D integer array nums where nums[i] is a non-empty array of distinct positive integers, return the list of integers that are present in each array of nums sorted in ascending order.
+ 
+
+Example 1:
+
+Input: nums = [[3,1,2,4,5],[1,2,3,4],[3,4,5,6]]  
+Output: [3,4]  
+Explanation:   
+The only integers present in each of nums[0] = [3,1,2,4,5], nums[1] = [1,2,3,4], and nums[2] = [3,4,5,6] are 3 and 4, so we return [3,4].  
+
+
+
+Example 2:
+
+Input: nums = [[1,2,3],[4,5,6]]  
+Output: []  
+Explanation:   
+There does not exist any integer present both in nums[0] and nums[1], so we return an empty list [].  
+ 
+
+Constraints:
+
+```text
+1 <= nums.length <= 1000  
+1 <= sum(nums[i].length) <= 1000  
+1 <= nums[i][j] <= 1000  
+All the values of nums[i] are unique.  
+```

go/intersectionOfMultipleArrays/go.mod

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+module intersectionOfMultipleArrays
+
+go 1.23.2

go/intersectionOfMultipleArrays/solution.go

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+package solution
+
+import "slices"
+
+func intersection(nums [][]int) []int {
+	// create a map to count occurrences of each number
+	counts := make(map[int]int)
+
+	// iterate through each array in nums
+	for _, n := range nums {
+		// increment the count for each number in the sub-slice
+		for _, v := range n {
+			counts[v]++
+		}
+	}
+
+	// store the number of input slices
+	n := len(nums)
+
+	// slice to store the numbers that appear in all slices
+	answer := []int{}
+
+	// iterate through the counts map
+	for k, v := range counts {
+		// if a number appears in all slices (count equals n)
+		if v == n {
+			// add it to the answer slice
+			answer = append(answer, k)
+		}
+	}
+
+	// sort the answser slice in ascending order
+	slices.Sort(answer)
+
+	// return the answer slice
+	return answer
+}

go/intersectionOfMultipleArrays/solution_test.go

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+package solution
+
+import (
+	"slices"
+	"testing"
+)
+
+func TestIntersection(t *testing.T) {
+	testCases := []struct {
+		name string
+		nums [][]int
+		want []int
+	}{
+		{
+			name: "test case one",
+			nums: [][]int{{3, 1, 2, 4, 5}, {1, 2, 3, 4}, {3, 4, 5, 6}},
+			want: []int{3, 4},
+		},
+		{
+			name: "test case two",
+			nums: [][]int{{1, 2, 3}, {4, 5, 6}},
+			want: []int{},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := intersection(tc.nums)
+
+			if !slices.Equal(got, tc.want) {
+				t.Errorf("got %v, want %v", got, tc.want)
+			}
+		})
+	}
+}