leetcode

1 Daily Problem, 2 Random

4 files changed, 83 insertions(+), 0 deletions(-)

diff --git a/ Problems/0354.cpp b/ Problems/0354.cpp

@@ -0,0 +1,21 @@

class Solution {

public:

int maxEnvelopes(vector<vector<int>> &envelopes) const {

const int n = size(envelopes);

sort(begin(envelopes), end(envelopes),

[](const auto &a, const auto &b) { return a[0] != b[0] ? a[0] < b[0] : a[1] > b[1]; });

vector<int> res;

for (int i = 0; i < n; i++) {

const auto crnt = envelopes[i][1];

const auto it = lower_bound(begin(res), end(res), crnt);

if (it == end(res))

res.push_back(crnt);

else

*it = crnt;

}

return size(res);

}

};

diff --git a/ Problems/0355.cpp b/ Problems/0355.cpp

@@ -0,0 +1,44 @@

class Twitter {

vector<pair<int, int>> posts[501];

bool following[501][501] = {0};

int time = 0;

public:

Twitter() {

for (int i = 0; i <= 500; i++) {

following[i][i] = true;

}

}

void postTweet(int userId, int tweetId) { posts[userId].emplace_back(time++, tweetId); }

vector<int> getNewsFeed(int userId) {

using type_t = tuple<int, int, int>;

static const auto cmp = [](const type_t &a, const type_t &b) { return get<0>(a) < get<0>(b); };

priority_queue<type_t, vector<type_t>, decltype(cmp)> pq(cmp);

for (int i = 0; i <= 500; i++) {

if (!following[userId][i]) continue;

const int n = size(posts[i]);

if (n == 0) continue;

pq.emplace(posts[i][n - 1].first, i, n - 1);

if (size(pq) > 10) pq.pop();

}

vector<int> res;

while (!pq.empty() && size(res) < 10) {

const auto [time, user, idx] = pq.top();

pq.pop();

res.push_back(posts[user][idx].second);

if (idx - 1 >= 0) pq.emplace(posts[user][idx - 1].first, user, idx - 1);

}

return res;

}

void follow(int followerId, int followeeId) { following[followerId][followeeId] = true; }

void unfollow(int followerId, int followeeId) { following[followerId][followeeId] = false; }

};

diff --git a/ Problems/2490.cpp b/ Problems/2490.cpp

@@ -0,0 +1,15 @@

class Solution {

public:

bool isCircularSentence(const string &sentence) const {

char prev = sentence.back();

stringstream ss(sentence);

string word;

while (ss >> word) {

if (word.front() != prev) return false;

prev = word.back();

}

return true;

}

};

diff --git a/ README.md b/ README.md

@@ -319,6 +319,8 @@ reference and a base for solving problems. | 0349 | Easy | [Intersection of Two Arrays](Problems/0349.cpp) | | 0350 | Easy | [Intersection of Two Arrays II](Problems/0350.cpp) | | 0352 | Hard | [Data Stream as Disjoint Intervals](Problems/0352.cpp) |

| 0354 | Hard | [Russian Doll Envelopes](Problems/0354.cpp) |

| 0355 | Medium | [Design Twitter](Problems/0355.cpp) |

| 0357 | Medium | [Count Numbers with Unique Digits](Problems/0357.cpp) | | 0367 | Easy | [Valid Perfect Square](Problems/0367.cpp) | | 0368 | Medium | [Largest Divisible Subset](Problems/0368.cpp) |

@@ -1288,6 +1290,7 @@ reference and a base for solving problems. | 2485 | Easy | [Find the Pivot Integer](Problems/2485.cpp) | | 2486 | Medium | [Append Characters to String to Make Subsequence](Problems/2486.cpp) | | 2487 | Medium | [Remove Nodes From Linked List](Problems/2487.cpp) |

| 2490 | Easy | [Circular Sentence](Problems/2490.cpp) |

| 2491 | Medium | [Divide Players Into Teams of Equal Skill](Problems/2491.cpp) | | 2492 | Medium | [Minimum Score of a Path Between Two Cities](Problems/2492.cpp) | | 2497 | Medium | [Maximum Star Sum of a Graph](Problems/2497.cpp) |