在网格上移动到目的地的方法数

/**
 * LeetCode 2912: Number of Ways to Move to a Destination on a Grid
 *
 * Problem Statement:
 * Given a m x n grid, you are initially located at the top-left corner (0, 0). You can only move either down or right
 * at any point in time. You are trying to reach the bottom-right corner (m-1, n-1). How many possible unique paths are there?
 *
 * Approach:
 * - Use dynamic programming with Java Streams to store the number of ways to reach each cell.
 * - Initialize the first row and first column to 1, since there's only one way to reach cells in the first row or column.
 * - For each cell (i, j), the number of ways to reach it is the sum of ways to reach the cell directly above it and the cell directly to the left of it.
 * - The value at the bottom-right corner of the grid will be the result.
 */
import java.util.stream.IntStream;

public class Solution {
    public int uniquePaths(int m, int n) {
        int[][] dp = new int[m][n];
        // Initialize the first row and first column using streams
        IntStream.range(0, m).forEach(i -> dp[i][0] = 1);
        IntStream.range(0, n).forEach(j -> dp[0][j] = 1);
        // Fill in the rest of the dp array using nested streams
        IntStream.range(1, m).forEach(i ->
            IntStream.range(1, n).forEach(j ->
                dp[i][j] = dp[i-1][j] + dp[i][j-1]
            )
        );
        return dp[m-1][n-1];
    }
}