Merge pull request #650 from openset/develop

Add: Accounts Merge

Author: Shuo

problems/accounts-merge/accounts_merge.go

@@ -1 +1,45 @@
 package accounts_merge
+
+import "sort"
+
+func accountsMerge(accounts [][]string) [][]string {
+	n := len(accounts)
+	owner := make(map[string]string, n)
+	parent := make(map[string]string, n*2)
+	for _, a := range accounts {
+		for i := 1; i < len(a); i++ {
+			parent[a[i]] = a[i]
+			owner[a[i]] = a[0]
+		}
+	}
+	for _, a := range accounts {
+		r := root(a[1], parent)
+		for i := 2; i < len(a); i++ {
+			p := root(a[i], parent)
+			parent[p] = r
+		}
+	}
+	union := make(map[string][]string, n)
+	for email, p := range parent {
+		r := root(p, parent)
+		union[r] = append(union[r], email)
+	}
+	res := make([][]string, 0, len(union))
+	for p, emails := range union {
+		t := make([]string, len(emails)+1)
+		t[0] = owner[p]
+		if len(emails) > 1 {
+			sort.Strings(emails)
+		}
+		copy(t[1:], emails)
+		res = append(res, t)
+	}
+	return res
+}
+
+func root(e string, parent map[string]string) string {
+	if parent[e] == e {
+		return e
+	}
+	return root(parent[e], parent)
+}

problems/accounts-merge/accounts_merge_test.go

@@ -1 +1,81 @@
 package accounts_merge
+
+import (
+	"reflect"
+	"sort"
+	"testing"
+)
+
+type caseType struct {
+	input    [][]string
+	expected [][]string
+}
+
+func TestAccountsMerge(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input: [][]string{
+				{"John", "[email protected]", "[email protected]"},
+				{"John", "[email protected]"},
+				{"John", "[email protected]", "[email protected]"},
+				{"Mary", "[email protected]"},
+			},
+			expected: [][]string{
+				{"John", "[email protected]", "[email protected]", "[email protected]"},
+				{"John", "[email protected]"},
+				{"Mary", "[email protected]"},
+			},
+		},
+		{
+			input: [][]string{
+				{"Alex", "[email protected]", "[email protected]", "[email protected]"},
+				{"Ethan", "[email protected]", "[email protected]", "[email protected]"},
+				{"Kevin", "[email protected]", "[email protected]", "[email protected]"},
+				{"Gabe", "[email protected]", "[email protected]", "[email protected]"},
+				{"Gabe", "[email protected]", "[email protected]", "[email protected]"},
+			},
+			expected: [][]string{
+				{"Alex", "[email protected]", "[email protected]", "[email protected]"},
+				{"Ethan", "[email protected]", "[email protected]"},
+				{"Gabe", "[email protected]", "[email protected]", "[email protected]", "[email protected]"},
+				{"Kevin", "[email protected]", "[email protected]"},
+			},
+		},
+		{
+			input: [][]string{
+				{"David", "[email protected]", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]", "[email protected]"},
+			},
+			expected: [][]string{
+				{"David", "[email protected]", "[email protected]", "[email protected]", "[email protected]", "[email protected]"},
+			},
+		},
+		{
+			input: [][]string{
+				{"David", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]"},
+				{"David", "[email protected]", "[email protected]"},
+			},
+			expected: [][]string{
+				{"David", "[email protected]", "[email protected]", "[email protected]", "[email protected]", "[email protected]", "[email protected]"},
+			},
+		},
+	}
+	for _, tc := range tests {
+		output := accountsMerge(tc.input)
+		sort.Slice(output, func(i, j int) bool {
+			if output[i][0] == output[i][0] {
+				return output[i][1] < output[j][1]
+			}
+			return output[i][0] < output[i][0]
+		})
+		if !reflect.DeepEqual(output, tc.expected) {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}