# 1048. Longest String Chain | LeetCode Solution

## 1048. Longest String Chain | LeetCode Solution

You are given an array of `words` where each word consists of lowercase English letters.

`wordA` is a predecessor of `wordB` if and only if we can insert exactly one letter anywhere in `wordA` without changing the order of the other characters to make it equal to `wordB`.

• For example, `"abc"` is a predecessor of `"abac"`, while `"cba"` is not a predecessor of `"bcad"`.

word chain is a sequence of words `[word1, word2, ..., wordk]` with `k >= 1`, where `word1` is a predecessor of `word2``word2` is a predecessor of `word3`, and so on. A single word is trivially a word chain with `k == 1`.

Return the length of the longest possible word chain with words chosen from the given list of `words`.

Example 1:

```Input: words = ["a","b","ba","bca","bda","bdca"]
Output: 4
Explanation: One of the longest word chains is ["a","ba","bda","bdca"].
```

Example 2:

```Input: words = ["xbc","pcxbcf","xb","cxbc","pcxbc"]
Output: 5
Explanation: All the words can be put in a word chain ["xb", "xbc", "cxbc", "pcxbc", "pcxbcf"].
```

Example 3:

```Input: words = ["abcd","dbqca"]
Output: 1
Explanation: The trivial word chain ["abcd"] is one of the longest word chains.
["abcd","dbqca"] is not a valid word chain because the ordering of the letters is changed.
```

Constraints:

• `1 <= words.length <= 1000`
• `1 <= words[i].length <= 16`
• `words[i]` only consists of lowercase English letters.

class Solution
{
public:
static bool cmp(string a, string b)
{
return a.length() < b.length();
}

int longestStrChain(vector<string> &v)
{
map<string, int> m;
int ans = 1;
sort(v.begin(), v.end(), cmp);
for (int i = 0; i < v.size(); i++)
{
string s = v[i];
int maxx = 0;
for (int j = 0; j < s.length(); j++)
{
string temp = s;
temp.erase(temp.begin() + j);
maxx = max(maxx, m[temp]);
}
m[s] = maxx + 1;
ans = max(ans, m[s]);
}
return ans;
}
};