Heap DS added

- Added Kth smallest element Kth largest element K sorted array K closest points to origin K frequent elements

Author: amn2

Heap/(1)KthSmallest.cpp

@@ -0,0 +1,33 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+// Kth smallest element
+priority_queue<int> heap; //max heap
+
+int Solve(int a[], int n, int k) {
+
+for (int i = 0; i < n; i++) {
+
+heap.push(a[i]);
+if (heap.size() > k) heap.pop();
+
+}
+
+return heap.top();
+}
+
+
+int main() {
+
+#ifndef ONLINE_JUDGE
+freopen("input.txt", "r", stdin);
+freopen("output.txt", "w", stdout);
+#endif
+
+int n, k;
+cin >> n >> k;
+int a[n];
+for (int i = 0; i < n; i++) cin >> a[i];
+
+cout << Solve(a, n, k) << endl;
+}

Heap/(2)KthLargest.cpp

@@ -0,0 +1,36 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+// Kth largest elements
+priority_queue<int, vector<int>, greater<int>> heap; //min heap
+
+void Solve(int a[], int n, int k) {
+
+for (int i = 0; i < n; i++) {
+
+heap.push(a[i]);
+if (heap.size() > k) heap.pop();
+
+}
+
+while (heap.size() > 0) {
+cout << heap.top() << " ";
+heap.pop();
+}
+}
+
+
+int main() {
+
+#ifndef ONLINE_JUDGE
+freopen("input.txt", "r", stdin);
+freopen("output.txt", "w", stdout);
+#endif
+
+int n, k;
+cin >> n >> k;
+int a[n];
+for (int i = 0; i < n; i++) cin >> a[i];
+
+Solve(a, n, k);
+}

Heap/(3)KSortedArray.cpp

@@ -0,0 +1,41 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+// Sort a k-sorted array or nearly sorted array
+// Element that should be present in sorted array is within the [i-k,i+k] range
+
+priority_queue<int, vector<int>, greater<int>> heap; //min heap
+
+void Solve(int a[], int n, int k) {
+
+for (int i = 0; i < n; i++) {
+
+heap.push(a[i]);
+if (heap.size() > k) {
+cout << heap.top() << " ";
+heap.pop();
+}
+
+}
+
+while (heap.size() > 0) {
+cout << heap.top() << " ";
+heap.pop();
+}
+}
+
+
+int main() {
+
+#ifndef ONLINE_JUDGE
+freopen("input.txt", "r", stdin);
+freopen("output.txt", "w", stdout);
+#endif
+
+int n, k;
+cin >> n >> k;
+int a[n];
+for (int i = 0; i < n; i++) cin >> a[i];
+
+Solve(a, n, k);
+}

Heap/(4)KClosestNo.cpp

@@ -0,0 +1,33 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+// K closest numbers to x
+
+priority_queue<pair<int, int>> heap; //max heap
+
+int main() {
+
+#ifndef ONLINE_JUDGE
+freopen("input.txt", "r", stdin);
+freopen("output.txt", "w", stdout);
+#endif
+
+int n, k;
+cin >> n >> k;
+int x;
+cin >> x;
+int a[n];
+for (int i = 0; i < n; i++) cin >> a[i];
+
+for (int i = 0; i < n; i++) {
+heap.push({abs(a[i] - x), a[i]});
+if (heap.size() > k) {
+heap.pop();
+}
+}
+
+while (heap.size() > 0) {
+cout << heap.top().second << " ";
+heap.pop();
+}
+}

Heap/(5)KFrequent.cpp

@@ -0,0 +1,35 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+// Top k frequent numbers
+
+priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> heap; // min heap
+
+int main() {
+
+#ifndef ONLINE_JUDGE
+freopen("input.txt", "r", stdin);
+freopen("output.txt", "w", stdout);
+#endif
+
+int n, k;
+cin >> n >> k;
+int a[n];
+unordered_map<int, int> m;
+
+for (int i = 0; i < n; i++) { cin >> a[i]; m[a[i]]++; }
+
+for (auto i : m) {
+heap.push({i.second, i.first});
+
+if (heap.size() > k) {
+heap.pop();
+}
+
+}
+
+while (heap.size() > 0) {
+cout << heap.top().second << " ";
+heap.pop();
+}
+}