Update

Author: harshit2608

Codechef/Chef_and_String.cpp

@@ -0,0 +1,21 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int solve(string s, int n)
+{
+    
+}
+
+int main()
+{
+    int testcase;
+    cin >> testcase;
+    while (testcase--)
+    {
+        string s;
+        cin >> s;
+        cout << solve(s, s.size());
+    }
+    return 0;
+}

InterViewBit/Greedy/Jump Game Array.cpp

@@ -0,0 +1,12 @@
+int Solution::canJump(vector<int> &A)
+{
+    int last = A.size() - 1;
+    for (int i = A.size() - 1; i >= 0; i--)
+    {
+        if (A[i] + i >= last)
+        {
+            last = i;
+        }
+    }
+    return last == 0;
+}

Leet Code/1137. N-th Tribonacci Number.cpp

@@ -0,0 +1,25 @@
+class Solution
+{
+public:
+    int tribonacci(int n)
+    {
+        if (n <= 1)
+        {
+            return n;
+        }
+        if (n == 2)
+        {
+            return 1;
+        }
+        int ans = 0;
+        int zero = 0, one = 1, two = 1;
+        for (int i = 3; i <= n; i++)
+        {
+            ans = zero + one + two;
+            zero = one;
+            one = two;
+            two = ans;
+        }
+        return ans;
+    }
+};

Leet Code/1365. How Many Numbers Are Smaller Than the Current Number.cpp

@@ -0,0 +1,20 @@
+class Solution
+{
+public:
+    vector<int> smallerNumbersThanCurrent(vector<int> &nums)
+    {
+
+        map<int, int> mp;
+        int n = nums.size();
+        vector<int> snum = nums;
+
+        sort(snum.begin(), snum.end());
+        for (int i = n - 1; i >= 0; i--)
+            mp[snum[i]] = i;
+
+        for (int i = 0; i < n; i++)
+            nums[i] = mp[nums[i]];
+
+        return nums;
+    }
+};

Leet Code/1389. Create Target Array in the Given Order.cpp

@@ -0,0 +1,13 @@
+class Solution
+{
+public:
+    vector<int> createTargetArray(vector<int> &nums, vector<int> &index)
+    {
+        vector<int> target;
+        for (int i = 0; i < nums.size(); ++i)
+        {
+            target.insert(target.begin() + index[i], nums[i]);
+        }
+        return target;
+    }
+};

Leet Code/1884. Egg Drop With 2 Eggs and N Floors.cpp

@@ -0,0 +1,8 @@
+class Solution
+{
+public:
+    int twoEggDrop(int n)
+    {
+        return (int)ceil((-1 + sqrt(1 + 8 * n)) / 2);
+    }
+};

Leet Code/53. Maximum Subarray.cpp

@@ -0,0 +1,16 @@
+class Solution
+{
+public:
+    int maxSubArray(vector<int> &nums)
+    {
+        int res = nums[0];
+        int maxending = nums[0];
+
+        for (int i = 1; i < nums.size(); i++)
+        {
+            maxending = max(nums[i], maxending + nums[i]);
+            res = max(res, maxending);
+        }
+        return res;
+    }
+};

Leet Code/912. Sort an Array.cpp

@@ -0,0 +1,79 @@
+//TODO: //*Correct Approach/
+class Solution
+{
+public:
+    int partition(vector<int> &nums, int l, int r)
+    {
+        int random = l + rand() % (r - l);
+        swap(nums[l], nums[random]);
+        int pivot = nums[l];
+        int i = l - 1, j = r + 1;
+
+        while (true)
+        {
+            do
+            {
+                i++;
+            } while (nums[i] < pivot);
+
+            do
+            {
+                j--;
+            } while (nums[j] > pivot);
+
+            if (i >= j)
+                return j;
+
+            swap(nums[i], nums[j]);
+        }
+    }
+
+    void quickSort(vector<int> &nums, int l, int r)
+    {
+        if (l >= r)
+        {
+            return;
+        }
+        int p = partition(nums, l, r);
+        quickSort(nums, l, p);
+        quickSort(nums, p + 1, r);
+    }
+    vector<int> sortArray(vector<int> &nums)
+    {
+        srand(time(NULL));
+        quickSort(nums, 0, nums.size() - 1);
+        return nums;
+    }
+};
+
+//FIXME: //* This approach uses recursion and those give TLE (NOTE: This approach was only used for learning reccursion)/
+// class Solution
+// {
+// public:
+//     void insert(vector<int> &nums, int temp)
+//     {
+//         if (nums.size() == 0 || nums[nums.size() - 1] <= temp)
+//         {
+//             nums.push_back(temp);
+//             return;
+//         }
+//         int val = nums[nums.size() - 1];
+//         nums.pop_back();
+//         insert(nums, temp);
+//         nums.push_back(val);
+//         return;
+//     }
+
+//     vector<int> sortArray(vector<int> &nums)
+//     {
+//         if (nums.size() == 1)
+//         {
+//             return nums;
+//         }
+//         int temp = nums[nums.size() - 1];
+//         nums.pop_back();
+//         sortArray(nums);
+//         insert(nums, temp);
+//         return nums;
+//     }
+// };

Self/Nqueen.cpp

@@ -0,0 +1,98 @@
+#include <vector>
+#include <iostream>
+
+using namespace std;
+bool isSafe(int ans[][10], int i, int j, int queens)
+{
+    //Check for top element
+    for (int row = 0; row < i; row++)
+    {
+        if (ans[row][j] == 1)
+        {
+            return false;
+        }
+    }
+    int x = i, y = j;
+    //Check for left diagonal
+    while (x >= 0 && y >= 0)
+    {
+        if (ans[x][y] == 1)
+        {
+            return false;
+        }
+        x--;
+        y--;
+    }
+
+    //Check right diagonal
+    x = i, y = j;
+    while (x >= 0 && y < queens)
+    {
+        if (ans[x][y] == 1)
+        {
+            return false;
+        }
+        x--;
+        y++;
+    }
+    return true;
+}
+
+bool solve(int ans[][10], int qpsf, int queens)
+{
+    if (qpsf == queens)
+    {
+        for (int i = 0; i < queens; i++)
+        {
+            for (int j = 0; j < queens; j++)
+            {
+                if (ans[i][j] == 1)
+                {
+                    cout << "Q ";
+                }
+                else
+                {
+                    cout << ". ";
+                }
+            }
+            cout << endl;
+        }
+        cout << endl;
+        return true;
+    }
+
+    for (int j = 0; j < queens; j++)
+    {
+        if (isSafe(ans, qpsf, j, queens))
+        {
+            ans[qpsf][j] = 1;
+            bool nextpq = solve(ans, qpsf + 1, queens);
+            if (nextpq)
+            {
+                return true;
+            }
+
+            ans[qpsf][j] = 0;
+        }
+    }
+    return false;
+}
+
+bool solveNqueens(int queens)
+{
+    int ans[10][10] = {0};
+    solve(ans, 0, queens);
+}
+
+int main()
+{
+    int t;
+    int queens;
+    cin >> t;
+    while (t--)
+    {
+        cin >> queens;
+        solveNqueens(queens);
+    }
+    return 0;
+}