LeetCode, GeeksForGeeks Problem of the day solution

class Solution { public: ListNode* removeNthFromEnd(ListNode* head, int n) { ListNode *fast = head, *slow = head; while(n--) fast = fast -> next; if(!fast) return head -> next; while(fast -> next) fast = fast -> next, slow = slow -> next; slow -> next = slow -> next -> next; return head; } };

class Solution{ public: // The main function that returns the arrangement with the largest value as // string. // The function accepts a vector of strings static bool cmp(string a,string b){ return a+b>b+a; } string printLargest(int n, vector &arr) { // code here sort(arr.begin(),arr.end(),cmp); string ans = ""; for(int i = 0;i

class Solution { public: vector sortedSquares(vector& nums) { for(auto &x : nums){ x = x*x; } sort(nums.begin(),nums.end()); return nums; } };

class Solution{ public: int firstElementKTime(int n, int k, int a[]) { std::unordered_map map; for(int i=0; i

class Solution { public: string maximumOddBinaryNumber(string s) { int i=s.length()-1; while(s[i]!='1') { i--; } swap(s[i],s[s.length()-1]); int l=0,r=i-1; while(l=0) { while(l<=r && r>=0 && s[r]=='1') { swap(s[l],s[r]); l++; } r--; } return s; } };

class Solution { public: int peakElement(int arr[], int n) { int ans=0; for(int i=0;iarr[i+1]){ ans=i; break; } else if(arr[i]>arr[i-1]){ ans=i; } } return ans; } };

class Solution { public: bool isEvenOddTree(TreeNode* root) { if(!root) return false; queueq; q.push(root); int lev=0; while(!q.empty()){ int n=q.size(); TreeNode* prev=NULL; while(n--) { TreeNode* cur=q.front(); q.pop(); if(lev%2==0){ if(cur->val % 2 == 0) return false; if(prev && prev->val>=cur->val) return false; }else{ if(cur->val % 2 == 1) return false; if(prev && prev->val<=cur->val) return false; } prev=cur; if(cur->left) q.push(cur->left); if(cur->right) q.push(cur->right); } lev++; } return true; } };

class Solution{ public: long long sumBitDifferences(int arr[], int n) { long long ans = 0; for(int k=0;k<32;k++){ int ct1 = 0; int ct0 = 0; for(int i=0;i>k)&1); if(t==1){ ct1++; } else{ ct0++; } } ans+=(ct1*(1ll)*ct0); } return ans*2; } };

class Solution { public: int findBottomLeftValue(TreeNode* root) { queue q; q.push(root); int ans = 0; while(!q.empty()){ int sz = q.size(); for(int i =0; i val; if(node->right) q.push(node -> right); if(node->left) q.push(node -> left); } } return ans; } };