You are given an array words of size n consisting of non-empty strings.
We define the score of a string word as the number of strings words[i] such that word is a prefix of words[i].
- For example, if
words = ["a", "ab", "abc", "cab"], then the score of"ab"is2, since"ab"is a prefix of both"ab"and"abc".
Return an array answer of size n where answer[i] is the sum of scores of every non-empty prefix of words[i].
Note that a string is considered as a prefix of itself.
Example 1:
Input: words = ["abc","ab","bc","b"] Output: [5,4,3,2] Explanation: The answer for each string is the following: - "abc" has 3 prefixes: "a", "ab", and "abc". - There are 2 strings with the prefix "a", 2 strings with the prefix "ab", and 1 string with the prefix "abc". The total is answer[0] = 2 + 2 + 1 = 5. - "ab" has 2 prefixes: "a" and "ab". - There are 2 strings with the prefix "a", and 2 strings with the prefix "ab". The total is answer[1] = 2 + 2 = 4. - "bc" has 2 prefixes: "b" and "bc". - There are 2 strings with the prefix "b", and 1 string with the prefix "bc". The total is answer[2] = 2 + 1 = 3. - "b" has 1 prefix: "b". - There are 2 strings with the prefix "b". The total is answer[3] = 2.
Example 2:
Input: words = ["abcd"] Output: [4] Explanation: "abcd" has 4 prefixes: "a", "ab", "abc", and "abcd". Each prefix has a score of one, so the total is answer[0] = 1 + 1 + 1 + 1 = 4.
Constraints:
1 <= words.length <= 10001 <= words[i].length <= 1000words[i]consists of lowercase English letters.
Use a trie to maintain the prefixes of all strings and the occurrence count of each prefix.
Then, traverse each string, accumulating the occurrence count of each prefix.
The time complexity is words and the maximum length of the strings in it, respectively.
class Trie:
def __init__(self):
self.children = [None] * 26
self.cnt = 0
def insert(self, w):
node = self
for c in w:
idx = ord(c) - ord('a')
if node.children[idx] is None:
node.children[idx] = Trie()
node = node.children[idx]
node.cnt += 1
def search(self, w):
node = self
ans = 0
for c in w:
idx = ord(c) - ord('a')
if node.children[idx] is None:
return ans
node = node.children[idx]
ans += node.cnt
return ans
class Solution:
def sumPrefixScores(self, words: List[str]) -> List[int]:
trie = Trie()
for w in words:
trie.insert(w)
return [trie.search(w) for w in words]class Trie {
private Trie[] children = new Trie[26];
private int cnt;
public void insert(String w) {
Trie node = this;
for (char c : w.toCharArray()) {
c -= 'a';
if (node.children[c] == null) {
node.children[c] = new Trie();
}
node = node.children[c];
++node.cnt;
}
}
public int search(String w) {
Trie node = this;
int ans = 0;
for (char c : w.toCharArray()) {
c -= 'a';
if (node.children[c] == null) {
return ans;
}
node = node.children[c];
ans += node.cnt;
}
return ans;
}
}
class Solution {
public int[] sumPrefixScores(String[] words) {
Trie trie = new Trie();
for (String w : words) {
trie.insert(w);
}
int[] ans = new int[words.length];
for (int i = 0; i < words.length; ++i) {
ans[i] = trie.search(words[i]);
}
return ans;
}
}class Trie {
private:
vector<Trie*> children;
int cnt;
public:
Trie()
: children(26)
, cnt(0) {}
void insert(string& w) {
Trie* node = this;
for (char c : w) {
int idx = c - 'a';
if (!node->children[idx]) node->children[idx] = new Trie();
node = node->children[idx];
++node->cnt;
}
}
int search(string& w) {
Trie* node = this;
int ans = 0;
for (char c : w) {
int idx = c - 'a';
if (!node->children[idx]) return ans;
node = node->children[idx];
ans += node->cnt;
}
return ans;
}
};
class Solution {
public:
vector<int> sumPrefixScores(vector<string>& words) {
Trie* trie = new Trie();
for (auto& w : words) {
trie->insert(w);
}
vector<int> ans;
for (auto& w : words) {
ans.push_back(trie->search(w));
}
return ans;
}
};type Trie struct {
children [26]*Trie
cnt int
}
func newTrie() *Trie {
return &Trie{}
}
func (this *Trie) insert(w string) {
node := this
for _, c := range w {
c -= 'a'
if node.children[c] == nil {
node.children[c] = newTrie()
}
node = node.children[c]
node.cnt++
}
}
func (this *Trie) search(word string) int {
node := this
ans := 0
for _, c := range word {
c -= 'a'
if node.children[c] == nil {
return ans
}
node = node.children[c]
ans += node.cnt
}
return ans
}
func sumPrefixScores(words []string) []int {
trie := newTrie()
for _, w := range words {
trie.insert(w)
}
ans := make([]int, len(words))
for i, w := range words {
ans[i] = trie.search(w)
}
return ans
}function sumPrefixScores(words: string[]): number[] {
const map = new Map();
for (const word of words) {
const n = word.length;
for (let i = 1; i <= n; i++) {
const s = word.slice(0, i);
map.set(s, (map.get(s) ?? 0) + 1);
}
}
return words.map(word => {
const n = word.length;
let count = 0;
for (let i = 1; i <= n; i++) {
const s = word.slice(0, i);
count += map.get(s);
}
return count;
});
}class Trie {
children: Array<any>;
cnt: number;
constructor() {
this.children = Array(26);
this.cnt = 0;
}
insert(w: string): void {
let node = this;
for (const c of w) {
const idx = c.charCodeAt(0) - 'a'.charCodeAt(0);
if (!node.children[idx]) {
node.children[idx] = new Trie();
}
node = node.children[idx];
node.cnt++;
}
}
search(w: string): number {
let node = this;
let ans = 0;
for (const c of w) {
const idx = c.charCodeAt(0) - 'a'.charCodeAt(0);
if (!node.children[idx]) {
return ans;
}
node = node.children[idx];
ans += node.cnt;
}
return ans;
}
}
function sumPrefixScores(words: string[]): number[] {
const trie = new Trie();
for (const w of words) {
trie.insert(w);
}
let ans = [];
for (const w of words) {
ans.push(trie.search(w));
}
return ans;
}