Merge pull request #586 from swarup-0508/main

Array Questions Contributed in C++

Author: gantavyamalviya

CPP/arrays/CheckifNandItsDoubleExist.cpp

@@ -0,0 +1,16 @@
+class Solution {
+public:
+    bool checkIfExist(vector<int>& arr) {
+        map<double,int> map;
+        for(int i = 0;i<arr.size();i++)
+        {
+            if(map.count((double)arr[i]*2) || (map.count((double)arr[i]/2)))
+            {
+                return true;
+            }
+            map[arr[i]]++;
+                
+        }
+        return false;
+    }
+};

CPP/arrays/DuplicateZeroes.cpp

@@ -0,0 +1,27 @@
+class Solution {
+public:
+
+        void insert(vector<int>& arr,int i,int j)
+         {
+          if(j<arr.size())
+                arr[j] = arr[i];
+        }
+        void duplicateZeros(vector<int>& arr) {
+        int zeroes=0;
+        for(int i : arr)
+        {
+            if(i==0)
+                zeroes++;
+        }
+
+        int i = arr.size()-1, j = arr.size()+zeroes-1;
+        while(i!=j)
+        {
+            insert(arr,i,j--);
+            if(arr[i]==0)
+            {
+                insert(arr,i,j--);
+            }
+            i--;
+        }
+    }

CPP/arrays/MergedSortedArray.cpp

@@ -0,0 +1,28 @@
+class Solution {
+public:
+    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
+
+        int i = m-1;
+        int j = n-1;
+        int k = m+n-1;
+        while(i>=0 && j>=0)
+        {
+            if(nums1[i]>nums2[j])
+            {
+                nums1[k--]=nums1[i--];
+            }
+            else
+            {
+                nums1[k--]=nums2[j--];
+            }
+        }
+        while(i>=0)
+        {
+            nums1[k--]=nums1[i--];
+        }
+        while(j>=0)
+        {
+            nums1[k--]=nums2[j--];
+        }
+    }
+};

CPP/arrays/RemoveDuplicatefromSortedArray.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+    int removeDuplicates(vector<int>& nums) {
+        vector<int> v;
+        vector<int> :: iterator it;
+
+        for(it = nums.begin();it!=nums.end();it++)
+        {
+            int ele = *it;
+            if(find(v.begin(),v.end(),ele)!=v.end())
+            {
+                nums.erase(it);
+                it--;
+            }
+            else
+                v.push_back(*it);
+
+        }
+        return nums.size();
+    }
+};

CPP/arrays/RemoveElement.cpp

@@ -0,0 +1,18 @@
+class Solution {
+public:
+    int removeElement(vector<int>& nums, int val) {
+        vector<int> :: iterator it;
+        it = nums.begin();
+        for(int i=0;i<nums.size();i++)
+        {
+            if(nums[i]==val)
+            {
+                nums.erase(it);
+                it--;
+                i--;
+            }
+            it++;
+        }
+        return nums.size();
+    }
+};

CPP/arrays/SortArraybyParity.cpp

@@ -0,0 +1,24 @@
+class Solution {
+public:
+    vector<int> sortArrayByParity(vector<int>& nums) {
+        int n = nums.size();
+        if(n==0 || n==1)
+        {return nums;}
+        
+        int i = 0,j=0;
+        while(i<n)
+        {
+            if(nums[i]%2!=0)
+            {
+                ++i;
+            }
+            else
+            {
+                swap(nums[i],nums[j]);
+                i++;
+                j++;
+            }
+        }
+        return nums;
+    }
+};

CPP/arrays/ValidMountainArray.cpp

@@ -0,0 +1,24 @@
+class Solution {
+public:
+    bool validMountainArray(vector<int>& arr) {
+        if(arr.size()<3) return false;
+        
+        int i = 0;
+        for(;i<arr.size()-1;i++)
+        {
+            if(arr[i]>arr[i+1])
+               { i++;
+                break;
+                }
+            else if(arr[i]==arr[i+1]) return false;
+        }
+        if(i<2) return false;
+        for(;i<arr.size();i++)
+        {
+            if(arr[i-1]<=arr[i])
+                return false;
+        }
+        return true;
+    }
+    
+};