Minimum Window Subsequence

class Solution {
public:
    string minWindow(string s, string t) {
        const int n = s.size(), m = t.size();
        int bestL = -1, bestLen = INT_MAX;
        int i = 0;
        while (i < n) {
            int j = 0;
            while (i < n && j < m) {
                if (s[i] == t[j]) ++j;
                ++i;
            }
            if (j < m) break;
            // Backward tighten from i-1.
            int r = i - 1, k = m - 1;
            while (k >= 0) {
                if (s[r] == t[k]) --k;
                --r;
            }
            int l = r + 1;
            if (i - l < bestLen) {
                bestLen = i - l;
                bestL = l;
            }
            i = l + 1;
        }
        return bestL < 0 ? "" : s.substr(bestL, bestLen);
    }
};

func minWindow(s string, t string) string {
    n, m := len(s), len(t)
    bestL, bestLen := -1, math.MaxInt32
    i := 0
    for i < n {
        j := 0
        for i < n && j < m {
            if s[i] == t[j] {
                j++
            }
            i++
        }
        if j < m {
            break
        }
        r, k := i-1, m-1
        for k >= 0 {
            if s[r] == t[k] {
                k--
            }
            r--
        }
        l := r + 1
        if i-l < bestLen {
            bestLen = i - l
            bestL = l
        }
        i = l + 1
    }
    if bestL < 0 {
        return ""
    }
    return s[bestL : bestL+bestLen]
}

class Solution:
    def minWindow(self, s: str, t: str) -> str:
        n, m = len(s), len(t)
        best_l, best_len = -1, float('inf')
        i = 0
        while i < n:
            j = 0
            while i < n and j < m:
                if s[i] == t[j]:
                    j += 1
                i += 1
            if j < m:
                break
            r, k = i - 1, m - 1
            while k >= 0:
                if s[r] == t[k]:
                    k -= 1
                r -= 1
            l = r + 1
            if i - l < best_len:
                best_len = i - l
                best_l = l
            i = l + 1
        if best_l < 0:
            return ""
        return s[best_l:best_l + best_len]

function minWindow(s, t) {
    const n = s.length, m = t.length;
    let bestL = -1, bestLen = Infinity;
    let i = 0;
    while (i < n) {
        let j = 0;
        while (i < n && j < m) {
            if (s[i] === t[j]) j++;
            i++;
        }
        if (j < m) break;
        let r = i - 1, k = m - 1;
        while (k >= 0) {
            if (s[r] === t[k]) k--;
            r--;
        }
        const l = r + 1;
        if (i - l < bestLen) {
            bestLen = i - l;
            bestL = l;
        }
        i = l + 1;
    }
    return bestL < 0 ? "" : s.substring(bestL, bestL + bestLen);
}

class Solution {
    public String minWindow(String s, String t) {
        int n = s.length(), m = t.length();
        int bestL = -1, bestLen = Integer.MAX_VALUE;
        int i = 0;
        while (i < n) {
            int j = 0;
            while (i < n && j < m) {
                if (s.charAt(i) == t.charAt(j)) j++;
                i++;
            }
            if (j < m) break;
            int r = i - 1, k = m - 1;
            while (k >= 0) {
                if (s.charAt(r) == t.charAt(k)) k--;
                r--;
            }
            int l = r + 1;
            if (i - l < bestLen) {
                bestLen = i - l;
                bestL = l;
            }
            i = l + 1;
        }
        return bestL < 0 ? "" : s.substring(bestL, bestL + bestLen);
    }
}

function minWindow(s: string, t: string): string {
    const n = s.length, m = t.length;
    let bestL = -1, bestLen = Infinity;
    let i = 0;
    while (i < n) {
        let j = 0;
        while (i < n && j < m) {
            if (s[i] === t[j]) j++;
            i++;
        }
        if (j < m) break;
        let r = i - 1, k = m - 1;
        while (k >= 0) {
            if (s[r] === t[k]) k--;
            r--;
        }
        const l = r + 1;
        if (i - l < bestLen) {
            bestLen = i - l;
            bestL = l;
        }
        i = l + 1;
    }
    return bestL < 0 ? "" : s.substring(bestL, bestL + bestLen);
}