1048 wrong answer

Author: aQuaYi

.vscode/settings.json

@@ -56,6 +56,7 @@
         "ctaagt",
         "ctxt",
         "cut",
+        "czvh",
         "deck",
         "dfs",
         "diff",
@@ -80,6 +81,10 @@
         "ghefcdab",
         "gitignore",
         "goconvey",
+        "gruj",
+        "grukj",
+        "grukkmj",
+        "grukmj",
         "hgfedcba",
         "i",
         "if",
@@ -94,6 +99,10 @@
         "keet",
         "keti",
         "keto",
+        "ksqsq",
+        "ksqvsq",
+        "ksqvsyq",
+        "kssq",
         "kyxfcuajfassqjfwa",
         "laiden",
         "leelee",
@@ -156,6 +165,12 @@
         "yllw",
         "yollew",
         "yollow",
+        "zcpzvh",
+        "zczpzfvdhx",
+        "zczpzvdhx",
+        "zczpzvh",
+        "zczpzvhx",
+        "zczvh",
         "zppedxfumcfsngp"
     ],
     "cSpell.language": "en,en-US"

Algorithms/1048.longest-string-chain/longest-string-chain.go

@@ -1,6 +1,53 @@
 package problem1048
 
 func longestStrChain(words []string) int {
+	lengths := make([][]string, 18)
+	minLen := 18
+	for _, w := range words {
+		l := len(w)
+		minLen = min(minLen, l)
+		lengths[l] = append(lengths[l], w)
+	}
 
-	return 0
+	res := 0
+	var dfs func(int, string)
+	dfs = func(count int, w1 string) {
+		l := len(w1) + 1
+		if len(lengths[l]) == 0 {
+			res = max(res, count)
+			return
+		}
+		for _, w2 := range lengths[l] {
+			if isPredecessor(w1, w2) {
+				dfs(count+1, w2)
+			}
+		}
+	}
+	for _, w1 := range lengths[minLen] {
+		dfs(1, w1)
+	}
+	return res
+}
+
+func isPredecessor(w1, w2 string) bool {
+	for i := 0; i < len(w2); i++ {
+		if w1[:i] == w2[:i] && w1[i:] == w2[i+1:] {
+			return true
+		}
+	}
+	return false
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
 }

Algorithms/1048.longest-string-chain/longest-string-chain_test.go

@@ -12,6 +12,11 @@ var tcs = []struct {
 	ans   int
 }{
 
+	{
+		[]string{"ksqvsyq", "ks", "kss", "czvh", "zczpzvdhx", "zczpzvh", "zczpzvhx", "zcpzvh", "zczvh", "gr", "grukmj", "ksqvsq", "gruj", "kssq", "ksqsq", "grukkmj", "grukj", "zczpzfvdhx", "gru"},
+		7,
+	},
+
 	{
 		[]string{"a", "b", "ba", "bca", "bda", "bdca"},
 		4,