[数据结构与算法]第 73 场双周赛

第 73 场双周赛

2190. 数组中紧跟 key 之后出现最频繁的数字

class Solution:
    def mostFrequent(self, nums: List[int], key: int) -> int:
        d = defaultdict(int)
        cnt = res = 0
        for i in range(1,len(nums)):
            k = nums[i]
            if nums[i-1] == key:
                d[k] += 1
                if d[k] > cnt:
                    res, cnt = k, d[k]

        return res

class Solution {
    public int mostFrequent(int[] nums, int key) {
        int[] cnt = new int[1001];
        int max = 0, res = 0;
        for (int i = 1; i < nums.length; i++){
            int k = nums[i];
            if (nums[i-1] == key){
                cnt[k]++;
                if (cnt[k] > max){
                    max = cnt[k];
                    res = k;
                }
            }
        }
        return res;
    }
}

2191. 将杂乱无章的数字排序

class Solution:
    def sortJumbled(self, mapping: List[int], nums: List[int]) -> List[int]:
        '''
        def comp(x):
            q = [str(mapping[int(d)]) for d in str(x)]
            return int(''.join(q))
        return sorted(nums, key = comp)
        '''
        return sorted(nums, key = lambda x : int(''.join(str(mapping[int(d)]) for d in str(x))))

2192. 有向无环图中一个节点的所有祖先

2193. 得到回文串的最少操作次数