Permutation in String

class Solution {
public:
    bool checkInclusion(string s1, string s2) {
        int n = s1.size(), m = s2.size();
        if (n > m) return false;
        int a[26] = {0}, b[26] = {0};
        for (int i = 0; i < n; ++i) { ++a[s1[i] - 'a']; ++b[s2[i] - 'a']; }
        if (memcmp(a, b, sizeof a) == 0) return true;
        for (int i = n; i < m; ++i) {
            ++b[s2[i] - 'a'];
            --b[s2[i - n] - 'a'];
            if (memcmp(a, b, sizeof a) == 0) return true;
        }
        return false;
    }
};

func checkInclusion(s1 string, s2 string) bool {
    n, m := len(s1), len(s2)
    if n > m {
        return false
    }
    var a, b [26]int
    for i := 0; i < n; i++ {
        a[s1[i]-'a']++
        b[s2[i]-'a']++
    }
    if a == b {
        return true
    }
    for i := n; i < m; i++ {
        b[s2[i]-'a']++
        b[s2[i-n]-'a']--
        if a == b {
            return true
        }
    }
    return false
}

class Solution:
    def checkInclusion(self, s1: str, s2: str) -> bool:
        n, m = len(s1), len(s2)
        if n > m:
            return False
        a = [0] * 26
        b = [0] * 26
        for i in range(n):
            a[ord(s1[i]) - ord('a')] += 1
            b[ord(s2[i]) - ord('a')] += 1
        if a == b:
            return True
        for i in range(n, m):
            b[ord(s2[i]) - ord('a')] += 1
            b[ord(s2[i - n]) - ord('a')] -= 1
            if a == b:
                return True
        return False

function checkInclusion(s1, s2) {
    const n = s1.length, m = s2.length;
    if (n > m) return false;
    const a = new Array(26).fill(0);
    const b = new Array(26).fill(0);
    const A = 'a'.charCodeAt(0);
    for (let i = 0; i < n; i++) {
        a[s1.charCodeAt(i) - A]++;
        b[s2.charCodeAt(i) - A]++;
    }
    const equal = () => {
        for (let i = 0; i < 26; i++) if (a[i] !== b[i]) return false;
        return true;
    };
    if (equal()) return true;
    for (let i = n; i < m; i++) {
        b[s2.charCodeAt(i) - A]++;
        b[s2.charCodeAt(i - n) - A]--;
        if (equal()) return true;
    }
    return false;
}

class Solution {
    public boolean checkInclusion(String s1, String s2) {
        int n = s1.length(), m = s2.length();
        if (n > m) return false;
        int[] a = new int[26];
        int[] b = new int[26];
        for (int i = 0; i < n; i++) {
            a[s1.charAt(i) - 'a']++;
            b[s2.charAt(i) - 'a']++;
        }
        if (Arrays.equals(a, b)) return true;
        for (int i = n; i < m; i++) {
            b[s2.charAt(i) - 'a']++;
            b[s2.charAt(i - n) - 'a']--;
            if (Arrays.equals(a, b)) return true;
        }
        return false;
    }
}

function checkInclusion(s1: string, s2: string): boolean {
    const n = s1.length, m = s2.length;
    if (n > m) return false;
    const a: number[] = new Array(26).fill(0);
    const b: number[] = new Array(26).fill(0);
    const A = 'a'.charCodeAt(0);
    for (let i = 0; i < n; i++) {
        a[s1.charCodeAt(i) - A]++;
        b[s2.charCodeAt(i) - A]++;
    }
    const equal = (): boolean => {
        for (let i = 0; i < 26; i++) if (a[i] !== b[i]) return false;
        return true;
    };
    if (equal()) return true;
    for (let i = n; i < m; i++) {
        b[s2.charCodeAt(i) - A]++;
        b[s2.charCodeAt(i - n) - A]--;
        if (equal()) return true;
    }
    return false;
}