Find All Anagrams in a String

class Solution {
public:
    vector<int> findAnagrams(string s, string p) {
        int n = s.size(), m = p.size();
        vector<int> ans;
        if (n < m) return ans;
        int need[26] = {0}, have[26] = {0};
        for (char c : p) ++need[c - 'a'];
        int matched = 0;
        for (int i = 0; i < 26; ++i) if (need[i] == 0) ++matched;
        for (int i = 0; i < n; ++i) {
            int add = s[i] - 'a';
            ++have[add];
            if (have[add] == need[add]) ++matched;
            else if (have[add] == need[add] + 1) --matched;
            if (i >= m) {
                int rem = s[i - m] - 'a';
                --have[rem];
                if (have[rem] == need[rem]) ++matched;
                else if (have[rem] == need[rem] - 1) --matched;
            }
            if (matched == 26) ans.push_back(i - m + 1);
        }
        return ans;
    }
};

func findAnagrams(s string, p string) []int {
    n, m := len(s), len(p)
    ans := []int{}
    if n < m {
        return ans
    }
    var need, have [26]int
    for i := 0; i < m; i++ {
        need[p[i]-'a']++
    }
    matched := 0
    for i := 0; i < 26; i++ {
        if need[i] == 0 {
            matched++
        }
    }
    for i := 0; i < n; i++ {
        add := s[i] - 'a'
        have[add]++
        if have[add] == need[add] {
            matched++
        } else if have[add] == need[add]+1 {
            matched--
        }
        if i >= m {
            rem := s[i-m] - 'a'
            have[rem]--
            if have[rem] == need[rem] {
                matched++
            } else if have[rem] == need[rem]-1 {
                matched--
            }
        }
        if matched == 26 {
            ans = append(ans, i-m+1)
        }
    }
    return ans
}

from typing import List

class Solution:
    def findAnagrams(self, s: str, p: str) -> List[int]:
        n, m = len(s), len(p)
        ans: List[int] = []
        if n < m:
            return ans
        need = [0] * 26
        have = [0] * 26
        for c in p:
            need[ord(c) - ord('a')] += 1
        matched = sum(1 for i in range(26) if need[i] == 0)
        for i in range(n):
            add = ord(s[i]) - ord('a')
            have[add] += 1
            if have[add] == need[add]:
                matched += 1
            elif have[add] == need[add] + 1:
                matched -= 1
            if i >= m:
                rem = ord(s[i - m]) - ord('a')
                have[rem] -= 1
                if have[rem] == need[rem]:
                    matched += 1
                elif have[rem] == need[rem] - 1:
                    matched -= 1
            if matched == 26:
                ans.append(i - m + 1)
        return ans

function findAnagrams(s, p) {
    const n = s.length, m = p.length;
    const ans = [];
    if (n < m) return ans;
    const need = new Array(26).fill(0);
    const have = new Array(26).fill(0);
    const A = 'a'.charCodeAt(0);
    for (let i = 0; i < m; i++) need[p.charCodeAt(i) - A]++;
    let matched = 0;
    for (let i = 0; i < 26; i++) if (need[i] === 0) matched++;
    for (let i = 0; i < n; i++) {
        const add = s.charCodeAt(i) - A;
        have[add]++;
        if (have[add] === need[add]) matched++;
        else if (have[add] === need[add] + 1) matched--;
        if (i >= m) {
            const rem = s.charCodeAt(i - m) - A;
            have[rem]--;
            if (have[rem] === need[rem]) matched++;
            else if (have[rem] === need[rem] - 1) matched--;
        }
        if (matched === 26) ans.push(i - m + 1);
    }
    return ans;
}

class Solution {
    public List<Integer> findAnagrams(String s, String p) {
        int n = s.length(), m = p.length();
        List<Integer> ans = new ArrayList<>();
        if (n < m) return ans;
        int[] need = new int[26];
        int[] have = new int[26];
        for (int i = 0; i < m; i++) need[p.charAt(i) - 'a']++;
        int matched = 0;
        for (int i = 0; i < 26; i++) if (need[i] == 0) matched++;
        for (int i = 0; i < n; i++) {
            int add = s.charAt(i) - 'a';
            have[add]++;
            if (have[add] == need[add]) matched++;
            else if (have[add] == need[add] + 1) matched--;
            if (i >= m) {
                int rem = s.charAt(i - m) - 'a';
                have[rem]--;
                if (have[rem] == need[rem]) matched++;
                else if (have[rem] == need[rem] - 1) matched--;
            }
            if (matched == 26) ans.add(i - m + 1);
        }
        return ans;
    }
}

function findAnagrams(s: string, p: string): number[] {
    const n = s.length, m = p.length;
    const ans: number[] = [];
    if (n < m) return ans;
    const need = new Array<number>(26).fill(0);
    const have = new Array<number>(26).fill(0);
    const A = 'a'.charCodeAt(0);
    for (let i = 0; i < m; i++) need[p.charCodeAt(i) - A]++;
    let matched = 0;
    for (let i = 0; i < 26; i++) if (need[i] === 0) matched++;
    for (let i = 0; i < n; i++) {
        const add = s.charCodeAt(i) - A;
        have[add]++;
        if (have[add] === need[add]) matched++;
        else if (have[add] === need[add] + 1) matched--;
        if (i >= m) {
            const rem = s.charCodeAt(i - m) - A;
            have[rem]--;
            if (have[rem] === need[rem]) matched++;
            else if (have[rem] === need[rem] - 1) matched--;
        }
        if (matched === 26) ans.push(i - m + 1);
    }
    return ans;
}