How hard is LeetCode 755. Pour Water?

LeetCode 755. Pour Water is rated Medium on LeetCode.

What is the time complexity of LeetCode 755. Pour Water?

The Python solution on this page runs in O(v \times n).

What is the space complexity of LeetCode 755. Pour Water?

The Python solution on this page uses O(1), where v and n are the number of water drops and the length of the height array, respectively auxiliary space.

What topics does LeetCode 755. Pour Water cover?

LeetCode 755. Pour Water is tagged Array and Simulation on LeetCode.

Is LeetCode 755. Pour Water a premium problem?

Yes. LeetCode 755. Pour Water is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

MediumNo. 0755LeetCode Premium

Pour Water — LeetCode 755 Python Solution

Topics: Array, Simulation
Reading time: 4 min
Source: leetcode.com

The problem

You are given an elevation map represents as an integer array heights where heights[i] representing the height of the terrain at index i. The width at each index is 1.

Example

Input: heights = [2,1,1,2,1,2,2], volume = 4, k = 3
Output: [2,2,2,3,2,2,2]
Explanation: The first drop of water lands at index k = 3. When moving left or right, the water can only move to the same level or a lower level. (By level, we mean the total height of the terrain plus any water in that column.)

Python solution

PythonSolution

class Solution:
    def pourWater(self, heights: List[int], volume: int, k: int) -> List[int]:
        for _ in range(volume):
            for d in (-1, 1):
                i = j = k
                while 0 <= i + d < len(heights) and heights[i + d] <= heights[i]:
                    if heights[i + d] < heights[i]:
                        j = i + d
                    i += d
                if j != k:
                    heights[j] += 1
                    break
            else:
                heights[k] += 1
        return heights

Complexity

Time: O(v × n)
Space · auxiliary: O(1)where v and n are the number of water drops and the length of the height array, respectively

Related problems
No.	Problem	Difficulty
0495	Teemo Attacking	Easy
0985	Sum of Even Numbers After Queries	Medium
1389	Create Target Array in the Given Order	Easy
1409	Queries on a Permutation With Key	Medium
1503	Last Moment Before All Ants Fall Out of a Plank	Medium
1535	Find the Winner of an Array Game	Medium

Frequently asked questions

How hard is LeetCode 755. Pour Water?: LeetCode 755. Pour Water is rated Medium on LeetCode.
What is the time complexity of LeetCode 755. Pour Water?: The Python solution on this page runs in O(v × n).
What is the space complexity of LeetCode 755. Pour Water?: The Python solution on this page uses O(1), where v and n are the number of water drops and the length of the height array, respectively auxiliary space.
What topics does LeetCode 755. Pour Water cover?: LeetCode 755. Pour Water is tagged Array and Simulation on LeetCode.
Is LeetCode 755. Pour Water a premium problem?: Yes. LeetCode 755. Pour Water is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

Stuck on problems like this in a live interview?

Stealth Interview is a desktop app for macOS and Windows. It reads the problem off your screen and returns a working solution with a step-by-step explanation and its time and space complexity, invisible to screen sharing.

Download for Mac Download for Windows

Free to download. Check it runs on your machine, then pick a plan.

90%Subscription

python

Please analyze this context and help me answer the question or solve the problem.

Transcript

"Okay, next one. Given a string, return the length of the longest substring that has no repeating characters. Walk me through your approach before you code it."

Technical interview · 45 minsolution.pyShared editor · Python 3Longest substring without repeatsMediumGiven a string s, return the length of the longest contiguous substring in which every character is unique.s = "abcabcbb"
→ 31def length_of_longest_substring(s: str) -> int:2 last_seen = {}3 left = best = 04 for right, ch in enumerate(s):5 if ch in last_seen and last_seen[ch] >= left:

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

GPT-6.1 Terra

Transcribing...

90%Subscription

python

Please analyze this context and help me answer the question or solve the problem.

Transcript

"Okay, next one. Given a string, return the length of the longest substring that has no repeating characters. Walk me through your approach before you code it."

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

GPT-6.1 TerraClear chat

Transcribing...

QuitEscHide+QCapture+PCrop+OSubmit+EnterPress to get answerLeft/Right+Up/Down+

90%Subscription

python

Please analyze this context and help me answer the question or solve the problem.

Transcript

"Okay, next one. Given a string, return the length of the longest substring that has no repeating characters. Walk me through your approach before you code it."

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

GPT-6.1 TerraClear chat

Transcribing...

Primary display

QuitEscHide+QCapture+PCrop+OSubmit+EnterPress to get answerLeft/Right+Up/Down+

The problem

Example

Python solution

Complexity

Related problems

Frequently asked questions

Stuck on problems like this in a live interview?

Approach

Approach

Approach