Leetcode 3160. Find the Number of Distinct Colors Among the Balls

• Leetcode 3160. Find the Number of Distinct Colors Among the Balls
  • 1. 解题思路
  • 2. 代码实现

• 题目链接：3160. Find the Number of Distinct Colors Among the Balls

1. 解题思路

这一题思路上同样比较清晰，我们只需用两个hash table来分别记录每一个位置的颜色以及每一个颜色当前出现的次数，此时，我们即可对每一次操作快速地维护和更新当前的distinct颜色的个数了。

2. 代码实现

给出python代码实现如下：

class Solution:
    def queryResults(self, limit: int, queries: List[List[int]]) -> List[int]:
        colors = {}
        cnt = defaultdict(int)
        distinct = 0
        ans = [0 for _ in queries]
        for i, (idx, c) in enumerate(queries):
            if idx not in colors:
                colors[idx] = c
                cnt[c] += 1
                if cnt[c] == 1:
                    distinct += 1
            else:
                oc = colors[idx]
                colors[idx] = c
                cnt[oc] -= 1
                if cnt[oc] == 0:
                    distinct -= 1
                cnt[c] += 1
                if cnt[c] == 1:
                    distinct += 1
            ans[i] = distinct
        return ans

提交代码评测得到：耗时1148ms，占用内存68.4MB。