Solution.ts

function minWindow(s1: string, s2: string): string {
    const m = s1.length;
    const n = s2.length;
    const f: number[][] = Array(m + 1)
        .fill(0)
        .map(() => Array(n + 1).fill(0));
    for (let i = 1; i <= m; ++i) {
        for (let j = 1; j <= n; ++j) {
            if (s1[i - 1] === s2[j - 1]) {
                f[i][j] = j === 1 ? i : f[i - 1][j - 1];
            } else {
                f[i][j] = f[i - 1][j];
            }
        }
    }
    let p = 0;
    let k = m + 1;
    for (let i = 1; i <= m; ++i) {
        if (s1[i - 1] === s2[n - 1] && f[i][n]) {
            const j = f[i][n] - 1;
            if (i - j < k) {
                k = i - j;
                p = j;
            }
        }
    }
    return k > m ? '' : s1.slice(p, p + k);
}