摘要：
public List<List> combinationSum(int[] candidates, int target) { List<List> ans = new ArrayList<>(); List combine = new ArrayList<>(); dfs(candidates, 阅读全文
摘要：
private boolean[][] r = new boolean[9][9]; private boolean[][] c = new boolean[9][9]; private boolean[][][] x = new boolean[3][3][9]; private boolean 阅读全文