题解 | #走方格的方案数#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    let args = [];
    while(line = await readline()){
        let tokens = line.split(' ');
        let a = parseInt(tokens[0]);
        let b = parseInt(tokens[1]);
        args = [a, b]
    }
    let n = args[0];
    let m = args[1];

    // let dp = new Array(n+1).fill(0).map(n1=>new Array(m+1).fill(0).map(m1=>1))
    
    // for(let i=1; i<=n; i++){
    //     for(let j=1; j<=m; j++){
    //     	if(i==1 && j==1) dp[1][1] = 2;
    //     	else if(i==2 && j==1) dp[2][1] = 3;
    // 		else if(i==1 && j==2) dp[1][2] = 3;
    // 		else dp[i][j] = dp[i][j-1] + dp[i-1][j]
    //     }
    // }
    let path=0
    function dfs(i,j){
        if(i==n && j==m){
            path ++
        }else{
            if(i+1<=n){dfs(i+1,j)}
            if(j+1<=m){dfs(i,j+1)}
        }
    }
    dfs(0, 0)
    console.log(path) 
    //return dp[n][m]
}()