#### Unique Paths

m
H
```/*
*
*  Unique Paths
*
*  There is a robot on an `m x n` grid.
*  The robot is initially located at the top-left corner.
*  The robot tries to move to the bottom-right corner.
*  The robot can only move either down or right at any point in time.
*
*  Given the two integers `m` and `n`,
*  return the number of possible unique paths that the robot can take to reach the bottom-right corner.
*/

/*
* @param {number} m
* @param {number} n
* @return {number}
*/

const uniquePaths = (m, n) => {
// only one way to reach end
if (m === 1 || n === 1) return 1

// build a linear grid of size m
// base case, position 1 has only 1 move
const paths = new Array(m).fill(1)

for (let i = 1; i < n; i++) {
for (let j = 1; j < m; j++) {
// paths[j] in RHS represents the cell value stored above the current cell
// paths[j-1] in RHS represents the cell value stored to the left of the current cell
// paths [j] on the LHS represents the number of distinct pathways to the cell (i,j)
paths[j] = paths[j - 1] + paths[j]
}
}
return paths[m - 1]
}

export { uniquePaths }
```