Merge pull request #60 from vaskoz/day25

Day25

README.md

@@ -38,3 +38,4 @@ problems from
 * [Day 22](https://github.com/vaskoz/dailycodingproblem-go/issues/53)
 * [Day 23](https://github.com/vaskoz/dailycodingproblem-go/issues/55)
 * [Day 24](https://github.com/vaskoz/dailycodingproblem-go/issues/57)
+* [Day 25](https://github.com/vaskoz/dailycodingproblem-go/issues/59)

day21/problem.go

@@ -13,7 +13,7 @@ type lectureEvent struct {
 	starting bool
 }
 
-// MinimumRooms calculates the minimum number of rooms to accomodate
+// MinimumRooms calculates the minimum number of rooms to accommodate
 // overlapping schedules.
 // Runtime is O(N log N) with O(2N) space
 func MinimumRooms(lectures []Lecture) int {

day25/problem.go

@@ -0,0 +1,30 @@
+package day25
+
+// Match returns if there is a regex match on the given input.
+func Match(input, pattern string) bool {
+	var ii, pi, missed int
+	for ii < len(input) && pi < len(pattern) && missed < 2 {
+		if pattern[pi] == '*' {
+			prev := pattern[pi-1]
+			var next byte
+			if pi+1 < len(pattern) {
+				next = pattern[pi+1]
+			}
+			for ii < len(input) && input[ii] != next {
+				if prev != '.' && input[ii] != prev {
+					return false
+				}
+				ii++
+			}
+			if ii == len(input) && pi < len(pattern)-1 {
+				return false
+			}
+			ii--
+		} else if pattern[pi] != '.' && input[ii] != pattern[pi] {
+			missed++
+		}
+		ii++
+		pi++
+	}
+	return ii == len(input) && pi == len(pattern)
+}

day25/problem_test.go

@@ -0,0 +1,36 @@
+package day25
+
+import "testing"
+
+var testcases = []struct {
+	input, pattern string
+	expected       bool
+}{
+	{"ray", "ra.", true},
+	{"raymond", "ra.", false},
+	{"chat", ".*at", true},
+	{"chats", ".*at", false},
+	{"chaaaa", "cha*", true},
+	{"raymond", "ra.*", true},
+	{"raymond", "ra.*d", true},
+	{"chaaab", "cha*", false},
+	{"chaaa", "cha*b", false},
+	{"abcd", "efg", false},
+	{"ab", "e", false},
+}
+
+func TestMatch(t *testing.T) {
+	for _, tc := range testcases {
+		if result := Match(tc.input, tc.pattern); result != tc.expected {
+			t.Errorf("Given (%v, %v), expected %v got %v", tc.input, tc.pattern, tc.expected, result)
+		}
+	}
+}
+
+func BenchmarkMatch(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range testcases {
+			Match(tc.input, tc.pattern)
+		}
+	}
+}