Weekly game 180 of leetcode – Python solution

Time:2021-9-17

5356. Lucky numbers in matrices

class Solution:
    def luckyNumbers (self, matrix: List[List[int]]) -> List[int]:
        rmin = [min(x) for x in matrix]
        cmax = []
        n = len(matrix)
        m = len(matrix[0])
        for i in range(m):
            maxv = matrix[0][i]
            for j in range(1, n):
                maxv = max(maxv, matrix[j][i])
            cmax.append(maxv)
        ans = []
        for i in range(n):
            for j in range(m):
                if matrix[i][j] == rmin[i] and matrix[i][j] == cmax[j]:
                    ans.append(matrix[i][j])
        return ans

5357. Design a stack that supports incremental operations

Create self. S = [] as stack. However, the first element in S is the real value, and the second is the added value. Each increment operation directly adds the elements in the stack, but records them in the list of elements at the corresponding position in the stack. They are not added up until pop, and are accumulated to the previous element.

class CustomStack:

    def __init__(self, maxSize: int):
        self.size = 0
        self.maxSize = maxSize
        self.s = []

    def push(self, x: int) -> None:
        if self.size < self.maxSize:
            self.s.append((x, 0)
            self.size += 1


    def pop(self) -> int:
        if self.size == 0:
            return -1
        x, inc = self.s.pop()
        if len(self.s) > 0:
            self.s[-1][1] += inc
        self.size -= 1
        return x + inc


    def increment(self, k: int, val: int) -> None:
        if self.size > 0:
            k -= 1
            k = min(k, self.size-1)
            self.s[k][1] += val

5179. Balance the binary search tree

My method is to traverse the tree – > turn to array – > sort – > build a binary search tree

class Solution:
    def balanceBST(self, root: TreeNode) -> TreeNode:
        ls = []
        def vis(t):
            if not t: return
            ls.append(t)
            vis(t.left)
            vis(t.right)
        vis(root)
        ls.sort(key=lambda t:t.val)
        def build(l, r):
            if l == r: 
                ls[l].left = None
                ls[l].right = None
                return ls[l]
            if l + 1 == r:
                ls[r].left = ls[l]
                ls[l].left = None
                ls[l].right = None
                ls[r].right = None
                return ls[r]
            mid = (l+r)>>1
            ls[mid].left = build(l, mid-1)
            ls[mid].right = build(mid+1, r)
            return ls[mid]
        return build(0, len(ls)-1)

5359. Maximum team performance value

First, arrange the efficiency from large to small, and set the rigid opening efficiency as the maximum value. This is that only the person with the highest efficiency can be selected, and then continuously reduce the efficiency. The lower the efficiency, the more people can be used. Each time, select k (if there are not enough people, select as many people as possible) who meet the efficiency requirements and have the highest speed.

Use the priority queue to maintain the speed of the currently selected everyone, so that the slowest person can be eliminated each time

import queue
class Solution:
    def maxPerformance(self, n: int, speed: List[int], efficiency: List[int], k: int) -> int:
        es = []
        for i in range(n):
            es.append((efficiency[i], speed[i]))
        es.sort(reverse=True)
        q = queue.PriorityQueue()
        q.put(es[0][1])
        mins = es[0][1]
        sm = mins
        mine = es[0][0]
        ans = sm * mine
        maxv = ans
        cur_min = -1
        for i in range(1, n):
            if i < k:
                q.put(es[i][1])
                sm += es[i][1]
                mine = min(mine, es[i][0])
                maxv = max(maxv, sm*mine)
            else:
                if cur_min == -1:
                    cur_min = q.get()
                if cur_min < es[i][0]:
                    sm += es[i][1]
                    sm -= cur_min
                    cur_min = -1
                    mine = min(mine, es[i][0])
                    maxv = max(maxv, sm*mine)
                    q.put(es[i][1])
        return maxv % 1000000007