Added more cpp files for solving!

coinprob.cpp

@@ -0,0 +1,41 @@
+
+#include <bits/stdc++.h>
+using namespace std;
+
+// All denominations of Indian Currency
+int deno[] = { 1, 2, 5, 10, 20,
+			50, 100, 500, 1000 };
+int n = sizeof(deno) / sizeof(deno[0]);
+
+void findMin(int V)
+{
+	sort(deno, deno + n);
+
+	// Initialize result
+	vector<int> ans;
+
+	// Traverse through all denomination
+	for (int i = n - 1; i >= 0; i--) {
+
+		// Find denominations
+		while (V >= deno[i]) {
+			V -= deno[i];
+			ans.push_back(deno[i]);
+		}
+	}
+
+	// Print result
+	for (int i = 0; i < ans.size(); i++)
+		cout << ans[i] << " ";
+}
+
+// Driver program
+int main()
+{
+	int n = 93;
+	cout << "Following is minimal"
+		<< " number of change for " << n
+		<< ": ";
+	findMin(n);
+	return 0;
+}

nqueen.cpp

@@ -0,0 +1,100 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int isSafe(int **arr, int x, int y, int n)
+{
+    //check for column
+    for (int row = 0; row < x; row++)
+    {
+        if (arr[row][y] == 1)
+        {
+            return false;
+        }
+    }
+
+    // for easy we are declaring variable
+    int row = x;
+    int col = y;
+
+    //check for upper right diagonal
+    while (row >= 0 && col <= n)
+    {
+        if (arr[row][col] == 1)
+        {
+            return false;
+        }
+        row--;
+        col++;
+    }
+    //reintialixing
+    row = x;
+    col = y;
+    //check for upper left diagonal
+    while (row >= 0 && col >= 0)
+    {
+        if (arr[row][col] == 1)
+        {
+            return false;
+        }
+        row--;
+        col++;
+    }
+    return true;
+}
+//not taking y because we will not check for the same row
+
+int nQueen(int **arr, int x, int n)
+{
+
+    //we have placed all the queens
+    if (x >= n)
+    {
+        return true;
+    }
+    for (int col = 0; col < n; col++)
+    {
+        if (isSafe(arr, x, col, n))
+        {
+            arr[x][col] = 1;
+
+            //now check for the other rows for queen placing
+            if (nQueen(arr, x + 1, n))
+            {
+                return true;
+            }
+
+            arr[x][col] = 0; //backtracking step if any one was found false
+        }
+    }
+    return false;
+}
+
+int main()
+{
+
+    int n;
+    cin >> n;
+
+    int **arr = new int *[n];
+    for (int i = 0; i < n; i++)
+    {
+        arr[i] = new int[n];
+        for (int j = 0; j < n; j++)
+        {
+            arr[i][j] = 0;
+        }
+    }
+
+    if (nQueen(arr, 0, n))
+    {
+        for (int i = 0; i < n; i++)
+        {
+            for (int j = 0; j < n; j++)
+            {
+                cout << arr[i][j] << " ";
+            }
+            cout << endl;
+        }
+    }
+    return 0;
+}

palindromeORnot.cpp

@@ -0,0 +1,20 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+
+    string str;
+    cin >> str;
+    int flag = 1;
+    int n = str.length();
+    for (int i = 0; i < str.length(); i++)
+    {
+        if (str[i] != str[n - i - 1])
+        {
+            flag = 0;
+            break;
+        }
+    }
+    cout << flag;
+}

printallduplicates.cpp

@@ -0,0 +1,28 @@
+//using map
+#include <bits/stdc++.h>
+using namespace std;
+
+void fun(string str)
+{
+
+    int n = str.length();
+    map<char, int> count;
+    for (int i = 0; i < n; i++)
+    {
+        count[str[i]]++;
+    }
+
+    for (auto it : count)
+    {
+        if (it.second > 1)
+            cout << it.first << " count = " << it.second << "\n";
+    }
+}
+
+int main()
+{
+    string str;
+    cin >> str;
+
+    fun(str);
+}

rat_maze.cpp

@@ -0,0 +1,79 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+bool isSafe(int **arr, int x, int y, int n)
+{
+
+    if (x < n && y < n && arr[x][y] == 1)
+    {
+        return true;
+    }
+    return false;
+}
+
+bool ratInMaze(int **arr, int x, int y, int n, int **sol)
+{
+    if ((x == (n - 1)) && (y == (n - 1)))
+    {
+        sol[x][y] = 1;
+        return true;
+    }
+    if (isSafe(arr, x, y, n))
+    {
+        sol[x][y] = 1;
+        if (ratInMaze(arr, x + 1, y, n, sol))
+        {
+            return true;
+        }
+        if (ratInMaze(arr, x, y + 1, n, sol))
+        {
+            return true;
+        }
+        sol[x][y] = 0; //bactracking
+        return false;
+    }
+    return false;
+}
+
+int main()
+{
+
+    int n;
+    cin >> n;
+    int **arr = new int *[n];
+    for (int i = 0; i < n; i++)
+    {
+        arr[i] = new int[n];
+    }
+    for (int i = 0; i < n; i++)
+    {
+        for (int j = 0; j < n; j++)
+        {
+            cin >> arr[i][j];
+        }
+    }
+
+    int **sol = new int *[n];
+    for (int i = 0; i < n; i++)
+    {
+        sol[i] = new int[n];
+        for (int j = 0; j < n; j++)
+        {
+            sol[i][j] = 0;
+        }
+    }
+
+    if (ratInMaze(arr, 0, 0, n, sol))
+    {
+        for (int i = 0; i < n; i++)
+        {
+            for (int j = 0; j < n; j++)
+            {
+                cout << sol[i][j] << " ";
+            }
+            cout << endl;
+        }
+    }
+
+    return 0;
+}

reversestring.cpp

@@ -0,0 +1,24 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+
+    string str;
+    cin >> str;
+
+    int n = str.length();
+    int end = n - 1;
+    int start = 0;
+
+    while (start < n / 2)
+    {
+        int temp = str[start];
+        str[start] = str[end];
+        str[end] = temp;
+
+        start++;
+        end--;
+    }
+    cout << str;
+}

stringsarerotation.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+
+    string s1, s2;
+    cin >> s1 >> s2;
+
+    int l1 = s1.length();
+    int l2 = s2.length();
+
+    if (l1 != l2)
+        cout << "NO" << endl;
+
+    else
+    {
+        string temp = s1 + s2;
+
+        if (temp.find(s2) != string::npos)
+        {
+            cout << "YES" << endl;
+        }
+
+        else
+            cout << "NO" << endl;
+    }
+
+    return 0;
+}