题解 | #放苹果#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
const map = new Map();
void (async function () {
    // Write your code here
    while ((line = await readline())) {
        let input = line.split(' ');
        let m = parseInt(input[0]);
        let n = parseInt(input[1]);
        console.log(getVal(m, n));
    }
})();

var getVal = function (m, n) {
    if (map.has(`${m}|${n}`)) return map.get(`${m}|${n}`);
	// 这里不等于 0 是因为当没有空盘子情况时，(2,2) 等价于 (0,2) 等价于 (0,1) 等于 1
    if (m < 0 || n < 0) return 0;
    if (m == 1 || n == 1) return 1;
    let val;
    if (m < n) {
		// 必有空盘子
        val = getVal(m, n - 1);
    } else {
		// 分为没有空盘子情况 + 有空盘子情况
        val = getVal(m - n, n) + getVal(m, n - 1);
    }
    map.set(`${m}|${n}`, val);
    return val;
};