add isomorphic strings

Author: kakugirai

README.md

@@ -28,7 +28,7 @@ Run `readme-generator.py`. Here you ≡Go!
 
 | Solved | Easy | Medium | Hard |
 | :----: | :--: | :----: | :--: |
-|155|85|61|9|
+|156|86|61|9|
 
 
 ## Solutions
@@ -121,6 +121,7 @@ Run `readme-generator.py`. Here you ≡Go!
 |200|[Number of Islands](https://leetcode.com/problems/number-of-islands)|Medium|[Go](src/number-of-islands/solution.go)|
 |202|[Happy Number](https://leetcode.com/problems/happy-number)|Easy|[Go](src/happy-number/solution.go)|
 |204|[Count Primes](https://leetcode.com/problems/count-primes)|Easy|[Go](src/count-primes/solution.go)|
+|205|[Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings)|Easy|[Go](src/isomorphic-strings/solution.go)|
 |206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list)|Easy|[Go](src/reverse-linked-list/solution.go)|
 |215|[Kth Largest Element in an Array](https://leetcode.com/problems/kth-largest-element-in-an-array)|Medium|[Go](src/kth-largest-element-in-an-array/solution.go)|
 |217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate)|Easy|[Go](src/contains-duplicate/solution.go)|

src/isomorphic-strings/solution.go

@@ -0,0 +1,30 @@
+package main
+
+import "fmt"
+
+func isIsomorphic(s string, t string) bool {
+	if len(s) != len(t) {
+		return false
+	}
+	return checkIsomorphic(s, t) && checkIsomorphic(t, s)
+}
+
+func checkIsomorphic(s string, t string) bool {
+	m := make(map[byte]byte)
+	for i := range s {
+		if _, ok := m[s[i]]; ok {
+			if m[s[i]] != t[i] {
+				return false
+			}
+		} else {
+			m[s[i]] = t[i]
+		}
+	}
+	return true
+}
+
+func main() {
+	s := "ab"
+	t := "aa"
+	fmt.Println(isIsomorphic(s, t))
+}

src/isomorphic-strings/solution_test.go

@@ -0,0 +1,31 @@
+package main
+
+import "testing"
+
+func Test_checkIsomorphic(t *testing.T) {
+	type args struct {
+		s string
+		t string
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			"1",
+			args{
+				s: "title",
+				t: "paper",
+			},
+			true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := checkIsomorphic(tt.args.s, tt.args.t); got != tt.want {
+				t.Errorf("checkIsomorphic() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}