Solution.ts

function uniquePaths(m: number, n: number): number {
    let dp = Array.from({ length: m }, v => new Array(n).fill(1));
    for (let i = 1; i < m; ++i) {
        for (let j = 1; j < n; ++j) {
            dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
        }
    }
    return dp[m - 1][n - 1];
}