added good questions based on heap data structure from leetcode

Heaps/Priority_Queues/1642. Furthest Building You Can Reach.cpp

@@ -0,0 +1,23 @@
+class Solution {
+public:
+    int furthestBuilding(vector<int>& h, int bricks, int ladders) {
+        int ans=0,sum=0,n=h.size();
+        priority_queue<int,vector<int>,greater<int>>pq;
+        for(int i=1;i<n;i++){
+            int diff=h[i]-h[i-1];
+            if(diff<=0){
+                ans=i;
+                continue;
+            }
+            pq.push(diff);
+            if(pq.size()>ladders){
+               sum+=pq.top();
+               pq.pop();
+               if(sum>bricks)break;
+            }
+            ans=i;
+        }
+        return ans;
+    }
+};
+//link->https://leetcode.com/problems/furthest-building-you-can-reach/

Heaps/Priority_Queues/1673. Find the Most Competitive Subsequence.cpp

@@ -0,0 +1,23 @@
+class Solution {
+public:
+    vector<int> mostCompetitive(vector<int>& nums, int k) {
+        stack<int>st;
+        vector<int>v(k);
+        int n=nums.size();
+        int nums_to_be_removed=n-k;
+        for(int i=0;i<n;i++){
+            while(!st.empty() && nums_to_be_removed>0 && st.top() > nums[i]){
+                st.pop();
+                nums_to_be_removed--;
+            }
+            st.push(nums[i]);
+        }
+        while(st.size()>k)st.pop();
+        for(int i=k-1;i>=0;i--){
+            v[i]=st.top();
+            st.pop();
+        }
+        return v;
+    }
+};
+//link->https://leetcode.com/problems/find-the-most-competitive-subsequence/

Heaps/Priority_Queues/347. Top K Frequent Elements.cpp

@@ -0,0 +1,20 @@
+class Solution {
+public:
+    vector<int> topKFrequent(vector<int>& nums, int k) {
+        vector<int>v;
+        priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>>pq;
+        unordered_map<int,int>mp;
+        for(auto it:nums)mp[it]++;
+        for(auto itr:mp){
+            pq.push({itr.second,itr.first});
+            if(pq.size()>k)pq.pop();
+        }
+        while(!pq.empty()){
+            v.push_back(pq.top().second);
+            pq.pop();
+        }
+        return v;
+
+    }
+};
+//link->https://leetcode.com/problems/top-k-frequent-elements/

Heaps/Priority_Queues/378. Kth Smallest Element in a Sorted Matrix.cpp

@@ -0,0 +1,27 @@
+class Solution {
+public:
+    #define pi pair<int,int>
+    int kthSmallest(vector<vector<int>>& mat, int k) {
+        priority_queue<pair<int,pi>,vector<pair<int,pi>>,greater<pair<int,pi>> >pq;
+        int n=mat.size(), m=mat[0].size();
+        pq.push({mat[0][0],{0,0}});
+        set<pi>vis;
+        vis.insert({0,0});
+        while(k>1){
+           int row=pq.top().second.first;
+           int col=pq.top().second.second;
+           pq.pop();
+           if(row+1<n && vis.find({row+1,col})==vis.end()){
+               pq.push({mat[row+1][col],{row+1,col}});
+               vis.insert({row+1,col});
+           }
+           if(col+1<m && vis.find({row,col+1})==vis.end()){
+               pq.push({mat[row][col+1],{row,col+1}});
+               vis.insert({row,col+1});
+           }
+           k--;
+        }
+        return pq.top().first;
+    }
+};
+//link->https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix/

Heaps/Priority_Queues/767. Reorganize String.cpp

@@ -0,0 +1,25 @@
+class Solution {
+public:
+    string reorganizeString(string s) {
+        unordered_map<char,int>mp;
+        for(auto c:s)mp[c]++;
+        priority_queue<pair<int,char>>pq;
+        for(auto itr:mp)pq.push({itr.second,itr.first});
+        auto temp1=pq.top();
+        pq.pop();
+        string ans="";
+        ans+=temp1.second;
+        temp1.first--;
+        while(!pq.empty()){
+            auto temp2=pq.top();
+            pq.pop();
+            ans+=temp2.second;
+            temp2.first--;
+            if(temp1.first>0)pq.push(temp1);
+            temp1=temp2;
+        }
+        if(temp1.first>0)return "";
+        return ans;
+    }
+};
+//link->https://leetcode.com/problems/reorganize-string/

bs.cpp

@@ -1,108 +1,108 @@
-// #include <bits/stdc++.h>
-// using namespace std;
-// int* bubbleSort(int arr[], int n) {
-
-
-//   for (int i = 0; i< n; i++) {
-
-
-//     for (int j = 0; j < n -1- i; j++) {
-
-
-//       if (arr[j] > arr[j + 1]) {
-//         int temp = arr[j];
-//         arr[j] = arr[j+ 1];
-//         arr[j + 1] = temp;
-//       }
-//     }
-//   }
-//   return arr;
-// }
-
-// int binarySearch(int arr[], int x, int low, int high) {
-
-
-//   while (low <= high) {
-//     int mid = low + high / 2;
-
-//     if (arr[mid] == x)
-//       return mid;
-
-//     if (arr[mid] < x)
-//       low = mid + 1;
-
-//     else
-//       high = mid - 1;
-//   }
-
-//   return -1;
-// }
-
-// int main() {
-//   int n,x;
-// 	cout<<"Enter the size of the array"<<endl;
-// 	cin>>n;
-// 	int arr[n];
-//     cout<<"Enter the elements of the array"<<endl;    
-// 	for(int i=0;i<n;i++)
-// 	cin>>arr[i];
-// 	cout<<"Enter the element you want to search in the array"<<endl;
-// 	cin>>x;
-//     bubbleSort(arr,n);
-//   int result = binarySearch(arr, x, 0, n-1 );
-//   if (result == -1)
-//     printf("Not found");
-//   else
-//     printf("Element is found at index %d", result);
-// }
-#include <bits/stdc++.h>
-using namespace std;
-void bubbleSort(int arr[], int n) {
-
-
-  for (int i = 0; i< n; i++) {
-    for (int j = 0; j < n -1- i; j++) {
-      if (arr[j] > arr[j + 1]) {
-        int temp = arr[j];
-        arr[j] = arr[j+ 1];
-        arr[j + 1] = temp;
-      }
-    }
-  }
-}
-
-int binarySearch(int arr[], int x, int low, int high) {
-  while (low <= high) {
-    int mid = low + high / 2;
-
-    if (arr[mid] == x)
-      return mid;
-
-    if (arr[mid] < x)
-      low = mid + 1;
-
-    else
-      high = mid - 1;
-  }
-
-  return -1;
-}
-
-int main() {
-  int n,x;
-    cout<<"Enter the size of the array"<<endl;
-    cin>>n;
-    int arr[n];
-    cout<<"Enter the elements of the array"<<endl;    
-    for(int i=0;i<n;i++)
-    cin>>arr[i];
-    cout<<"Enter the element you want to search in the array"<<endl;
-    cin>>x;
-
-    bubbleSort(arr,n);
-  int result = binarySearch(arr, x, 0, n-1 );
-  if (result == -1)
-    printf("Element is not present in the array");
-  else
-    printf("Element is found at position %d", result +1);
-}
+// #include <bits/stdc++.h>
+// using namespace std;
+// int* bubbleSort(int arr[], int n) {
+
+
+//   for (int i = 0; i< n; i++) {
+
+
+//     for (int j = 0; j < n -1- i; j++) {
+
+
+//       if (arr[j] > arr[j + 1]) {
+//         int temp = arr[j];
+//         arr[j] = arr[j+ 1];
+//         arr[j + 1] = temp;
+//       }
+//     }
+//   }
+//   return arr;
+// }
+
+// int binarySearch(int arr[], int x, int low, int high) {
+
+
+//   while (low <= high) {
+//     int mid = low + high / 2;
+
+//     if (arr[mid] == x)
+//       return mid;
+
+//     if (arr[mid] < x)
+//       low = mid + 1;
+
+//     else
+//       high = mid - 1;
+//   }
+
+//   return -1;
+// }
+
+// int main() {
+//   int n,x;
+// 	cout<<"Enter the size of the array"<<endl;
+// 	cin>>n;
+// 	int arr[n];
+//     cout<<"Enter the elements of the array"<<endl;    
+// 	for(int i=0;i<n;i++)
+// 	cin>>arr[i];
+// 	cout<<"Enter the element you want to search in the array"<<endl;
+// 	cin>>x;
+//     bubbleSort(arr,n);
+//   int result = binarySearch(arr, x, 0, n-1 );
+//   if (result == -1)
+//     printf("Not found");
+//   else
+//     printf("Element is found at index %d", result);
+// }
+#include <bits/stdc++.h>
+using namespace std;
+void bubbleSort(int arr[], int n) {
+
+
+  for (int i = 0; i< n; i++) {
+    for (int j = 0; j < n -1- i; j++) {
+      if (arr[j] > arr[j + 1]) {
+        int temp = arr[j];
+        arr[j] = arr[j+ 1];
+        arr[j + 1] = temp;
+      }
+    }
+  }
+}
+
+int binarySearch(int arr[], int x, int low, int high) {
+  while (low <= high) {
+    int mid = low + high / 2;
+
+    if (arr[mid] == x)
+      return mid;
+
+    if (arr[mid] < x)
+      low = mid + 1;
+
+    else
+      high = mid - 1;
+  }
+
+  return -1;
+}
+
+int main() {
+  int n,x;
+    cout<<"Enter the size of the array"<<endl;
+    cin>>n;
+    int arr[n];
+    cout<<"Enter the elements of the array"<<endl;    
+    for(int i=0;i<n;i++)
+    cin>>arr[i];
+    cout<<"Enter the element you want to search in the array"<<endl;
+    cin>>x;
+
+    bubbleSort(arr,n);
+  int result = binarySearch(arr, x, 0, n-1 );
+  if (result == -1)
+    printf("Element is not present in the array");
+  else
+    printf("Element is found at position %d", result +1);
+}