unique-paths.js

/**
 * @param {number} m
 * @param {number} n
 * @return {number}
 */
const uniquePaths = (m, n) => {
  const dp = Array(m);
  for (let i = 0; i < m; i++) {
    dp[i] = Array(n).fill(0);
  }

  
  for (let j = 0; j < n; j++) {
    dp[0][j] = 1;
  }

 
  for (let i = 0; i < m; i++) {
    dp[i][0] = 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];
};