Add solution for problem 3043 (#6)

Author: eselyavka

problems/3001-3300/p3043/solution_3043.go

@@ -0,0 +1,31 @@
+package p3043
+
+import "strconv"
+
+func longestCommonPrefix(arr1 []int, arr2 []int) int {
+	prefixes := make(map[int]struct{})
+
+	for _, num := range arr1 {
+		for num > 0 {
+			prefixes[num] = struct{}{}
+			num /= 10
+		}
+	}
+
+	ans := 0
+
+	for _, num := range arr2 {
+		for num > 0 {
+			if _, ok := prefixes[num]; ok {
+				numStr := strconv.Itoa(num)
+				if len(numStr) > ans {
+					ans = len(numStr)
+					break
+				}
+			}
+			num /= 10
+		}
+	}
+
+	return ans
+}

problems/3001-3300/p3043/solution_3043_test.go

@@ -0,0 +1,13 @@
+package p3043
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSolution3043(t *testing.T) {
+	assert.Equal(t, 3, longestCommonPrefix([]int{1, 10, 100}, []int{1000}), "example 1")
+	assert.Equal(t, 0, longestCommonPrefix([]int{1, 2, 3}, []int{4, 4, 4}), "example 2")
+	assert.Equal(t, 4, longestCommonPrefix([]int{5655359, 1223}, []int{56554, 789}), "shared multi-digit prefix")
+}