From f22311cdfed5d7e271c808f32f931f5fa5171d69 Mon Sep 17 00:00:00 2001
From: rihib <rihib@rihib.dev>
Date: Fri, 16 Aug 2024 00:06:25 +0900
Subject: [PATCH] pullrequests/is_subsequence

---
 pullrequests/is_subsequence/step1.go | 23 +++++++++++++++++++++++
 pullrequests/is_subsequence/step2.go | 21 +++++++++++++++++++++
 pullrequests/is_subsequence/step3.go | 16 ++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 pullrequests/is_subsequence/step1.go
 create mode 100644 pullrequests/is_subsequence/step2.go
 create mode 100644 pullrequests/is_subsequence/step3.go

diff --git a/pullrequests/is_subsequence/step1.go b/pullrequests/is_subsequence/step1.go
new file mode 100644
index 0000000..1f76dc4
--- /dev/null
+++ b/pullrequests/is_subsequence/step1.go
@@ -0,0 +1,23 @@
+//lint:file-ignore U1000 Ignore all unused code
+package issubsequence
+
+/*
+時間：10分
+思っていたよりも時間がかかってしまった。
+*/
+func isSubsequenceStep1(s string, t string) bool {
+	current := 0
+	for i := 0; i < len(s); i++ {
+		for {
+			if current >= len(t) {
+				return false
+			}
+			if s[i] == t[current] {
+				current++
+				break
+			}
+			current++
+		}
+	}
+	return true
+}
diff --git a/pullrequests/is_subsequence/step2.go b/pullrequests/is_subsequence/step2.go
new file mode 100644
index 0000000..2dd1019
--- /dev/null
+++ b/pullrequests/is_subsequence/step2.go
@@ -0,0 +1,21 @@
+//lint:file-ignore U1000 Ignore all unused code
+package issubsequence
+
+/*
+よりシンプルにした。
+*/
+func isSubsequenceStep2(s string, t string) bool {
+	if len(s) == 0 {
+		return true
+	}
+	current := 0
+	for i := 0; i < len(t); i++ {
+		if s[current] == t[i] {
+			current++
+		}
+		if current == len(s) {
+			return true
+		}
+	}
+	return false
+}
diff --git a/pullrequests/is_subsequence/step3.go b/pullrequests/is_subsequence/step3.go
new file mode 100644
index 0000000..5e12304
--- /dev/null
+++ b/pullrequests/is_subsequence/step3.go
@@ -0,0 +1,16 @@
+//lint:file-ignore U1000 Ignore all unused code
+package issubsequence
+
+/*
+おそらくこれが一番シンプルなのではないだろうか。
+*/
+func isSubsequenceStep3(s string, t string) bool {
+	i, j := 0, 0
+	for i < len(s) && j < len(t) {
+		if s[i] == t[j] {
+			i++
+		}
+		j++
+	}
+	return i == len(s)
+}