【算法】力扣第 284 场周赛（最短代码）

6031. 找出数组中的所有 K 近邻下标

看数据范围1 <= nums.length <= 1000，直接暴力2行搞定

class Solution:
    def findKDistantIndices(self, nums: List[int], key: int, k: int) -> List[int]:
        keys = [i for i,v in enumerate(nums) if v == key]
        return sorted({j  for i in keys for j in range(len(nums)) if abs(i - j) <= k})

5203. 统计可以提取的工件

看数据范围1 <= n <= 1000，每个工件最多只覆盖4个单元格，直接哈希+暴力，2行搞定

class Solution:
    def digArtifacts(self, n: int, artifacts: List[List[int]], dig: List[List[int]]) -> int:
        map = set([(a, b) for a, b in dig])
        return sum(all((i, j) in map for i in range(r1, r2+1) for j in range(c1, c2+1)) for r1, c1, r2, c2 in artifacts)

5227. K 次操作后最大化顶端元素

这题比较吃细节，推荐大家看一下灵茶山艾府大佬的题解，1行就搞定了

class Solution:
    def maximumTop(self, nums: List[int], k: int) -> int:
        return max(num for i, num in enumerate(nums) if i < k - 1 or i == k) if len(nums) > 1 or k % 2 == 0 else -1

6032. 得到要求路径的最小带权子图

三次dijkstra，可可也是看了题解之后才做出来，15行解法👇

class Solution:
    def minimumWeight(self, n: int, edges: List[List[int]], src1: int, src2: int, dest: int) -> int:
        g1,g2=defaultdict(lambda:defaultdict(lambda:inf)),defaultdict(lambda:defaultdict(lambda:inf))
        for u,v,w in edges:
            g1[u][v],g2[v][u]=min(g1[u][v],w),min(g2[v][u],w)
        
        def dijkstra(graph,s):
            dist=[inf]*n;dist[s]=0
            heap=[];heappush(heap,(0,s))
            while heap:
                d,u=heappop(heap)
                for v in graph[u]:
                    if graph[u][v]+d<dist[v]:
                        dist[v]=graph[u][v]+d
                        heappush(heap,(dist[v],v))
            return dist
        
        a,b,c=dijkstra(g1,src1),dijkstra(g1,src2),dijkstra(g2,dest)

        return res if (res:=min(a[i]+b[i]+c[i] for i in range(n)))<inf else -1

总结

T4罚坐一小时/(ㄒoㄒ)/~~，T1+T2+T3+T4共2+2+1+15=20行代码，勉强完成【20行完成周赛】的目标！