完成「最长公共前缀」

longest-common-prefix.go

@@ -0,0 +1,31 @@
+package leetcode
+
+func longestCommonPrefix(strs []string) string {
+	if len(strs) == 0 {
+		return ""
+	}
+	if len(strs) == 1 {
+		return strs[0]
+	}
+	var index int
+	first := strs[0]
+	secList := strs[1:]
+	max := len(first)
+	for _, str := range secList {
+		l := len(str)
+		if l < max {
+			max = l
+		}
+	}
+OUTLOOP:
+	for i := 0; i < max; i++ {
+		c := first[i : i+1]
+		for _, str := range secList {
+			if str[i:i+1] != c {
+				break OUTLOOP
+			}
+		}
+		index = i + 1
+	}
+	return first[:index]
+}

longest-common-prefix_test.go

@@ -0,0 +1,33 @@
+package leetcode
+
+import (
+	"testing"
+)
+
+func TestLongestCommonPrefix(t *testing.T) {
+	qsts := []question{
+		question{
+			Q: []string{},
+			A: "",
+		},
+		question{
+			Q: []string{"abc"},
+			A: "abc",
+		},
+		question{
+			A: "fl",
+			Q: []string{"flower", "flow", "flight"},
+		},
+		question{
+			A: "",
+			Q: []string{"dog", "racecar", "car"},
+		},
+	}
+	for _, q := range qsts {
+		qst := q.Q.([]string)
+		res := q.A.(string)
+		if r := longestCommonPrefix(qst); r != res {
+			t.Fatalf("quest is: %+v, except result is: %v, but exec result is: %v", qst, res, r)
+		}
+	}
+}

question.go

@@ -0,0 +1,6 @@
+package leetcode
+
+type question struct {
+	Q interface{}
+	A interface{}
+}