leetcode

LeetCode 75 I: Day 15 FINISH

3 files changed, 67 insertions(+), 0 deletions(-)

diff --git a/ Problems/0692.cpp b/ Problems/0692.cpp

@@ -0,0 +1,46 @@

// sort: O(nlogn)

class Solution {

public:

vector<string> topKFrequent(const vector<string> &words, int k) {

unordered_map<string, int> um;

for (const auto &w : words) um[w]++;

vector<pair<int, string>> vec(um.size());

vector<string> res(k);

int count = 0;

for (const auto &[k, v] : um) vec[count++] = {-v, k};

sort(vec.begin(), vec.end());

for (int i = 0; i < k; i++) res[i] = vec[i].second;

return res;

}

};

// heap: O(nlogk)

class Solution {

typedef pair<string, int> psi;

static constexpr const auto cmp = [](const psi &p1, const psi &p2) {

if (p1.second == p2.second) return p1.first < p2.first;

return p1.second > p2.second;

};

public:

vector<string> topKFrequent(const vector<string> &words, int k) {

unordered_map<string, int> um;

for (const auto &w : words) um[w]++;

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

vector<string> res(k);

for (auto it : um) {

pq.push(it);

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

}

int count = k - 1;

while (!pq.empty()) res[count--] = pq.top().first, pq.pop();

return res;

}

};

diff --git a/ Problems/1046.cpp b/ Problems/1046.cpp

@@ -0,0 +1,19 @@

class Solution {

public:

int lastStoneWeight(vector<int> &stones) {

int n = stones.size();

make_heap(stones.begin(), stones.end());

while (stones.size() > 1) {

int x, y;

pop_heap(stones.begin(), stones.end());

y = stones.back(), stones.pop_back();

pop_heap(stones.begin(), stones.end());

x = stones.back(), stones.pop_back();

if (x != y) {

stones.push_back(y - x);

push_heap(stones.begin(), stones.end());

}

}

return !stones.empty() ? stones.back() : 0;

}

};

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

@@ -229,6 +229,7 @@ for solving problems. | 0669 | Medium | [Trim a Binary Search Tree](Problems/0669.cpp) | | 0671 | Easy | [Second Minimum Node In a Binary Tree](Problems/0671.cpp) | | 0684 | Medium | [Redundant Connection](Problems/0684.cpp) |

| 0692 | Medium | [Top K Frequent Words](Problems/0692.cpp) |

| 0695 | Medium | [Max Area of Island](Problems/0695.cpp) | | 0700 | Easy | [Search in a Binary Search Tree](Problems/0700.cpp) | | 0701 | Medium | [Insert into a Binary Search Tree](Problems/0701.cpp) |

@@ -290,6 +291,7 @@ for solving problems. | 1026 | Medium | [Maximum Difference Between Node and Ancestor](Problems/1026.cpp) | | 1038 | Medium | [Binary Search Tree to Greater Sum Tree](Problems/1038.cpp) | | 1042 | Medium | [Flower Planting With No Adjacent](Problems/1042.cpp) |

| 1046 | Easy | [Last Stone Weight](Problems/1046.cpp) |

| 1047 | Easy | [Remove All Adjacent Duplicates In String](Problems/1047.cpp) | | 1051 | Easy | [Height Checker](Problems/1051.cpp) | | 1061 | Medium | [Lexicographically Smallest Equivalent String](Problems/1061.cpp) |