题解 | #走方格的方案数#

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.Stream;

import static java.util.Arrays.*;
import static java.util.stream.Stream.*;


public class Main {
    public static void main(String[] args) throws IOException {

        //testCompletePack();
        testTh();
    }

    private static void testTh() throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        String str;
        while ((str = bf.readLine()) != null) {
            String[] split = str.split(" ");
            int row = Integer.parseInt(split[0]);
            int line = Integer.parseInt(split[1]);
            int[][] dp = new int[Integer.parseInt(split[0]) + 1][Integer.parseInt(
                        split[1]) + 1];
            for (int i = 0; i <= row; i++) {
                dp[i][0] = 1;
            }
            for (int i = 0; i <= line; i++) {
                dp[0][i] = 1;
            }

            for (int i = 1; i <= row; i++) {
                for (int j = 1; j <= line; j++) {
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
                }
            }
            System.out.println(dp[row][line]);
        }

    }




}