Merge a7b94a5 into 421fffa

README.md

@@ -162,3 +162,4 @@ problems from
 * [Day 149](https://github.com/vaskoz/dailycodingproblem-go/issues/311)
 * [Day 150](https://github.com/vaskoz/dailycodingproblem-go/issues/312)
 * [Day 151](https://github.com/vaskoz/dailycodingproblem-go/issues/313)
+* [Day 153](https://github.com/vaskoz/dailycodingproblem-go/issues/316)

day153/problem.go

@@ -0,0 +1,45 @@
+package day153
+
+import (
+	"strings"
+)
+
+// SmallestDistanceBetweenWords returns the smallest number of words
+// between the two given words in the text provided.
+// Returns -1 if one or both of the words don't exist in the text.
+func SmallestDistanceBetweenWords(text, one, two string) int {
+	words := strings.Split(text, " ")
+	oneI := getIndex(words, one, 0)
+	twoI := getIndex(words, two, 0)
+	if oneI == -1 || twoI == -1 {
+		return -1
+	}
+	smallest := len(words)
+	for oneI != -1 && twoI != -1 {
+		if dist := abs(oneI - twoI); dist < smallest {
+			smallest = dist
+		}
+		if oneI < twoI {
+			oneI = getIndex(words, one, oneI+1)
+		} else {
+			twoI = getIndex(words, two, twoI+1)
+		}
+	}
+	return smallest - 1
+}
+
+func getIndex(s []string, target string, start int) int {
+	for i := start; i < len(s); i++ {
+		if s[i] == target {
+			return i
+		}
+	}
+	return -1
+}
+
+func abs(a int) int {
+	if a < 0 {
+		return -a
+	}
+	return a
+}

day153/problem_test.go

@@ -0,0 +1,29 @@
+package day153
+
+import "testing"
+
+var testcases = []struct {
+	text, one, two string
+	expected       int
+}{
+	{"dog cat hello cat dog dog hello cat world", "hello", "world", 1},
+	{"dog cat hello cat dog dog hello cat world", "hello", "cat", 0},
+	{"dog cat hello cat dog dog hello cat world", "wat?", "cat", -1},
+}
+
+func TestSmallestDistanceBetweenWords(t *testing.T) {
+	t.Parallel()
+	for _, tc := range testcases {
+		if result := SmallestDistanceBetweenWords(tc.text, tc.one, tc.two); result != tc.expected {
+			t.Errorf("Expected %v got %v", tc.expected, result)
+		}
+	}
+}
+
+func BenchmarkSmallestDistanceBetweenWords(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range testcases {
+			SmallestDistanceBetweenWords(tc.text, tc.one, tc.two)
+		}
+	}
+}