2209. 用地毯覆盖后的最少白色砖块

题目链接：2209. 用地毯覆盖后的最少白色砖块

代码如下：

class Solution {
public:
	int minimumWhiteTiles(string floor, int numCarpets, int carpetLen) {
		vector<vector<int>>memo (numCarpets + 1, vector<int>(floor.size(), -1));//-1表示没有计算过
		auto dfs = [&](auto&& dfs, int i, int j)->int {
			if (j < carpetLen * i) {//剩余砖块全部可以覆盖
				return 0;
			}
			int& res = memo[i][j];
			if (res != -1) {
				return res;
			}
			if (i == 0) {
				return res = dfs(dfs, i, j - 1) + (floor[j] - '0');
			}
			return res = min(dfs(dfs, i, j - 1) + (floor[j] - '0'), dfs(dfs, i - 1, j - carpetLen));
		};
		return dfs(dfs,numCarpets, floor.size() - 1);
	}
};