Added multiple array dsa programmes

CPP/Array/firstandlastpositionofelement.cpp

@@ -0,0 +1,49 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Solution
+{
+public:
+    vector<int> searchRange(vector<int> &nums, int target)
+    {
+        int k = nums.size() - 1;
+        vector<int> v(2, 0);
+        int f = 0, l = 0;
+
+        for (int i = 0; i < nums.size(); i++)
+        {
+            if (f == 0 && nums[i] == target)
+            {
+                v[0] = i;
+                f = 1;
+            }
+            if (l == 0 && nums[k] == target)
+            {
+                v[1] = k;
+                l = 1;
+            }
+            if (f == 1 && l == 1)
+                return v;
+            k--;
+        }
+
+        // If not found
+        v = {-1, -1};
+        return v;
+    }
+};
+
+int main()
+{
+    Solution s;
+    vector<int> nums = {5, 7, 7, 8, 8, 10};
+    int target = 8;
+
+    vector<int> result = s.searchRange(nums, target);
+
+    cout << "Target " << target << " found at range: ["
+         << result[0] << ", " << result[1] << "]" << endl;
+
+    return 0;
+}

CPP/Array/nextpermutation.cpp

@@ -0,0 +1,74 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Solution
+{
+public:
+    void nextPermutation(vector<int> &nums)
+    {
+        int y = -1;
+        if (nums.size() == 1)
+            return;
+
+        // Step 1: find the first decreasing element from the end
+        for (int i = nums.size() - 2; i >= 0; i--)
+        {
+            if (nums[i] < nums[i + 1])
+            {
+                y = i;
+                break;
+            }
+        }
+
+        // Step 2: if found, swap it with the next larger element from the end
+        if (y != -1)
+        {
+            for (int j = nums.size() - 1; j > y; j--)
+            {
+                if (nums[y] < nums[j])
+                {
+                    swap(nums[y], nums[j]);
+                    break;
+                }
+            }
+            // Step 3: reverse the part after index y
+            rev(nums, y + 1, nums.size() - 1);
+        }
+        else
+        {
+            // If no such index found, reverse the whole array
+            rev(nums, 0, nums.size() - 1);
+        }
+    }
+
+    void rev(vector<int> &nums, int l, int r)
+    {
+        while (l < r)
+        {
+            swap(nums[l], nums[r]);
+            l++;
+            r--;
+        }
+    }
+};
+
+int main()
+{
+    Solution s;
+    vector<int> nums = {1, 2, 3};
+
+    cout << "Original permutation: ";
+    for (int n : nums)
+        cout << n << " ";
+    cout << endl;
+
+    s.nextPermutation(nums);
+
+    cout << "Next permutation: ";
+    for (int n : nums)
+        cout << n << " ";
+    cout << endl;
+
+    return 0;
+}

CPP/Array/removeduplicatefromsortedarray.cpp

@@ -0,0 +1,42 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Solution
+{
+public:
+    int removeDuplicates(vector<int> &nums)
+    {
+        if (nums.empty())
+            return 0; // Handle empty vector case
+
+        int r = 1;
+        for (int i = 1; i < nums.size(); i++)
+        {
+            if (nums[i] != nums[r - 1])
+            {
+                nums[r] = nums[i];
+                r++;
+            }
+        }
+        return r;
+    }
+};
+
+int main()
+{
+    Solution s;
+    vector<int> nums = {0, 0, 1, 1, 1, 2, 2, 3, 3, 4};
+
+    int newLength = s.removeDuplicates(nums);
+
+    cout << "New length: " << newLength << endl;
+    cout << "Array after removing duplicates: ";
+    for (int i = 0; i < newLength; i++)
+    {
+        cout << nums[i] << " ";
+    }
+    cout << endl;
+
+    return 0;
+}

CPP/Array/removeelement.cpp

@@ -0,0 +1,40 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Solution
+{
+public:
+    int removeElement(vector<int> &nums, int val)
+    {
+        int k = 0;
+        for (int i = 0; i < nums.size(); i++)
+        {
+            if (nums[i] != val)
+            {
+                nums[k] = nums[i];
+                k++;
+            }
+        }
+        return k;
+    }
+};
+
+int main()
+{
+    Solution s;
+    vector<int> nums = {3, 2, 2, 3};
+    int val = 3;
+
+    int newLength = s.removeElement(nums, val);
+
+    cout << "New length: " << newLength << endl;
+    cout << "Array after removing " << val << ": ";
+    for (int i = 0; i < newLength; i++)
+    {
+        cout << nums[i] << " ";
+    }
+    cout << endl;
+
+    return 0;
+}

CPP/Array/twosum.cpp

@@ -0,0 +1,49 @@
+// Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
+
+// You may assume that each input would have exactly one solution, and you may not use the same element twice.
+
+// You can return the answer in any order.
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Solution
+{
+public:
+    vector<int> twoSum(vector<int> &nums, int target)
+    {
+        vector<int> v;
+        for (int i = 0; i < nums.size(); i++)
+        {
+            for (int j = i + 1; j < nums.size(); j++)
+            {
+                if (nums[j] + nums[i] == target)
+                {
+                    v = {j, i};
+                    return v;
+                }
+            }
+        }
+        return v;
+    }
+};
+
+int main()
+{
+    Solution s;
+    vector<int> nums = {2, 7, 11, 15};
+    int target = 9;
+
+    vector<int> result = s.twoSum(nums, target);
+
+    if (!result.empty())
+    {
+        cout << "Indices: " << result[0] << " and " << result[1] << endl;
+    }
+    else
+    {
+        cout << "No two numbers found that add up to target." << endl;
+    }
+
+    return 0;
+}