Algorithms

Author: deepakkasera

Diff for: Arrays&Strings/NQueenProblem.cpp

@@ -0,0 +1,72 @@
+#include <bits/stdc++.h>
+using namespace std;
+bool isSafe(int board[][10],int i,int j,int n){
+	//check for the column
+	for(int x=0;x<i;x++){
+		if(board[x][j]==1)
+			return false;
+	}
+	
+	//Check for top left diagonal
+	int x=i,y=j;
+	while(x>=0 && y>=0){
+		if(board[x][y]==1){
+			return false;
+		}
+		x--;
+		y--;
+	}
+
+	//Check for top right diagonal
+	x=i,y=j;
+	while(x>=0 && y<n){
+		if(board[x][y]==1){
+			return false;
+		}
+		x--;
+		y++;
+	}
+
+	//if position is safe to place the queen
+	return true;
+
+}
+bool solveNQueen(int board[][10],int i,int n){
+	//Base Case
+	if(i==n){
+		//Print the board
+		for(int i=0;i<n;i++){
+			for(int j=0;j<n;j++){
+				if(board[i][j]){
+					cout << "Q ";
+				}
+				else
+					cout << ". ";
+			}
+			cout << endl;
+		}
+		return true;
+	}
+	//Recursive Case
+	for(int j=0;j<n;j++){
+		//Lets try to place the queen at jth column
+		if(isSafe(board,i,j,n)){
+			board[i][j] = 1;
+			bool nextQueen = solveNQueen(board,i+1,n);
+			if(nextQueen==true){
+				return true;
+			}
+			board[i][j] = 0;
+		}
+	}
+	return false;
+}
+int main(int argc, char const *argv[])
+{
+	int n;
+	cout << "Enter the value of n\n";
+	cin >> n;
+	int board[10][10] = {0};
+	solveNQueen(board,0,n);
+	return 0;
+}

Diff for: Arrays&Strings/a.out

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+using namespace std;
+void permutations(string s,int i){
+	if(i==s.length()){
+		cout << s << endl;
+		return ;
+	}
+	for(int j=i;j<s.length();j++){
+		swap(s[i],s[j]);
+		permutations(s,i+1);
+		swap(s[i],s[j]);
+	}
+	return;
+}
+int main(int argc, char const *argv[])
+{
+	string s;
+	cin >> s;
+	cout << "permutations\n";
+	permutations(s,0);
+	// cout << "string " << s << endl;
+	return 0;
+}

Diff for: Arrays&Strings/permutationsOfString.cpp

@@ -67,10 +67,10 @@ std::vector<int> factorizationlog(int n){
 	std::vector<int> res;
 	std::map<int,int> m;
 	std::map<int,int>::iterator it;
-		while(n != 1){
-			res.push_back(minPrime[n]);
-			m[minPrime[n]]++;
-			n /= minPrime[n];
+	while(n != 1){
+		res.push_back(minPrime[n]);
+		m[minPrime[n]]++;
+		n /= minPrime[n];
 	}
 	cout << "map is \n";
 	for(it=m.begin();it!=m.end();it++){
@@ -79,8 +79,6 @@ std::vector<int> factorizationlog(int n){
 	cout << endl;
 	return res;
 }
-
-
 int main(int argc, char const *argv[])
 {
 	int n;