Apr13 and Apr14 result push

daily/Apr13.cpp

@@ -0,0 +1,91 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+ public:
+  /**
+   * @brief Just like map, change the value of edges
+   * Time: O(n), only one traverse
+   * @param n, edges
+   * @return int
+   */
+  int findChampion(int n, vector<vector<int>>& edges) {
+    vector<int> ans(n);
+    for (auto& edge : edges) ans[edge[1]]++;
+
+    int champion = -1;
+    for (int i = 0; i < n; i++) {
+      if (ans[i] == 0) {
+        if (champion != -1) return -1;
+        champion = i;
+      }
+    }
+    return champion;
+  }
+
+  // Same idea, same way
+  int findChampion1(int n, vector<vector<int>>& edges) {
+    vector<int> is_weak(n);
+    for (auto& e : edges) {
+      is_weak[e[1]] = true;  // not chapion, in degree > 0
+    }
+
+    int ans = -1;
+    for (int i = 0; i < n; i++) {
+      if (is_weak[i]) {
+        continue;
+      }
+      if (ans != -1) {
+        return -1;  // more than one champion
+      }
+      ans = i;
+    }
+    return ans;
+  }
+};
+
+class MovingAverage {
+  int size;
+  double sum;
+  queue<int> q;
+
+ public:
+  // MovingAverage(int size) {
+  //   this->size = size;
+  //   this->sum = 0.0;
+  // }
+
+  // this 2 types of construtor works same way
+  MovingAverage(int size) : size(size), sum(0.0) {}
+
+  double next(int val) {
+    if (size == q.size()) {
+      sum -= q.front();
+      q.pop();
+    }
+    q.emplace(val);
+    sum += val;
+    return sum / q.size();
+  }
+};
+
+class Contest138 {
+ public:
+  int scoreOfString(string s) {
+    int res = 0;
+    for (int i = 1; i < s.size(); i++) {
+      res += abs(s[i] - s[i - 1]);
+    }
+    return res;
+  }
+
+  // int minRectanglesToCoverPoints(vector<vector<int>>& points, int w) {
+  //   // no need to care about hhe second value
+  //   int xsz = points.size();
+  //   unordered_map<int, int> mp;
+  //   for (int i = 0; i < xsz; i++) {
+  //     // int x = points[i];
+  //     mp[points[i]]++;
+  //   }
+  // }
+};

daily/Apr14.cpp

@@ -0,0 +1,192 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+ public:
+};
+
+/**
+ * @brief We use the vector and list to
+ * Implement the hashset here
+ */
+class MyHashSet {
+  vector<list<int>> data;
+  static const int base = 769;
+  static int hash(int key) { return key % base; }
+
+ public:
+  MyHashSet() : data(base) {}
+
+  void add(int key) {
+    int h = hash(key);
+    for (auto it = data[h].begin(); it != data[h].end(); it++) {
+      if ((*it) == key) {
+        return;
+      }
+    }
+    data[h].push_back(key);
+  }
+
+  void remove(int key) {
+    int h = hash(key);
+    for (auto it = data[h].begin(); it != data[h].end(); it++) {
+      if ((*it) == key) {
+        data[h].erase(it);
+        return;
+      }
+    }
+  }
+
+  bool contains(int key) {
+    int h = hash(key);
+    for (auto it = data[h].begin(); it != data[h].end(); it++) {
+      if ((*it) == key) return true;
+    }
+    return false;
+  }
+};
+
+struct Node {
+  int key, val;
+  int freq;
+  Node *prev, *next;
+  Node() : key(0), val(0), prev(nullptr), next(nullptr) {}
+  Node(int key_, int val_)
+      : key(key_), val(val_), prev(nullptr), next(nullptr) {}
+  Node() : key(-1), val(-1), freq(0), prev(nullptr), next(nullptr) {}
+  Node(int key_, int val_)
+      : key(key_), val(val_), freq(1), prev(nullptr), next(nullptr) {}
+};
+
+struct FreqList {
+  int freq;
+  Node *vhead, *vtail;
+  FreqList(int freq_) : freq(freq_), vhead(new Node()), vtail(new Node()) {
+    vhead->next = vtail;
+    vtail->prev = vhead;
+  }
+};
+
+class LRUCache {
+  unordered_map<int, Node*> cache;
+  int size;
+  Node *head, *tail;
+
+ public:
+  LRUCache(int capacity_) : size(capacity_) {
+    head = new Node();
+    tail = new Node();
+    head->next = tail;
+    tail->prev = head;
+  }
+
+  void addHead(Node* node) {
+    node->next = head->next;
+    node->prev = head->prev;
+    head->next->prev = node;
+    head->next = node;
+  }
+
+  void deleteNode(Node* node) {
+    node->prev->next = node->next;
+    node->next->prev = node->prev;
+  }
+
+  void popTail() {
+    Node* node = tail->prev;
+    deleteNode(node);
+    cache.erase(node->key);
+  }
+
+  int get(int key) {
+    int res = -1;
+    if (cache.find(key) != cache.end()) {
+      // find
+      Node* node = cache[key];
+      res = node->val;
+      deleteNode(node);
+      addHead(node);
+    }
+    return res;
+  }
+
+  void put(int key, int value) {
+    if (size == 0) return;
+    if (get(key) != -1) {
+      cache[key]->val = value;
+    } else {
+      if (size == cache.size()) {
+        popTail();
+      }
+      Node* node = new Node(key, value);
+      cache[key] = node;
+      addHead(node);
+    }
+  }
+};
+
+class LFUCache {
+  unordered_map<int, Node*> cache;
+  unordered_map<int, FreqList*> freq_map;
+  int size;
+  int min_freq;
+
+ public:
+  LFUCache(int capacity_) : size(capacity_) {}
+
+  bool isEmpty(FreqList* list) {
+    return list->vhead->next == list->vtail ? true : false;
+  }
+
+  void addHead(Node* node) {
+    int freq = node->freq;
+    if (freq_map.find(freq) == freq_map.end()) {
+      freq_map[freq] = new FreqList(freq);
+    }
+    FreqList* list = freq_map[freq];
+    node->next = list->vhead->next;
+    node->prev = list->vhead->next->prev;
+    list->vhead->next->prev = node;
+    list->vhead->next = node;
+  }
+
+  void deleteNode(Node* node) {
+    node->prev->next = node->next;
+    node->next->prev = node->prev;
+  }
+
+  void popTail() {
+    Node* node = freq_map[min_freq]->vtail->prev;
+    deleteNode(node);
+    cache.erase(node->key);
+  }
+
+  int get(int key) {
+    int res = -1;
+    if (cache.find(key) != cache.end()) {
+      Node* node = cache[key];
+      res = node->val;
+      deleteNode(node);
+      node->freq++;
+      if (isEmpty(freq_map[min_freq])) min_freq++;
+      addHead(node);
+    }
+    return res;
+  }
+
+  void put(int key, int value) {
+    if (size == 0) return;
+    if (get(key) != -1) {
+      // exist
+      cache[key]->val = value;
+    } else {
+      if (size == cache.size()) {
+        popTail();
+      }
+      Node* node = new Node(key, value);
+      addHead(node);
+      min_freq = 1;
+      cache[key] = node;
+    }
+  }
+};