Language: C++


//include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <fstream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <string>
#include <cstring>
#include <ctime>
#include <limits>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }

//math
//-------------------------------------------
template<class T> inline T sqr(T x) { return x * x; }

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define EXISTch(s,c) ((((s).find_first_of(c)) != std::string::npos)? 1 : 0)//cがあれば1 if(1)
#define SORT(c) sort((c).begin(),(c).end())

#define REP(i,n) for(int i=0;i<(int)n;++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI = acos(-1.0);
const int INF = (int)1000000007;
const LL MOD = (LL)1000000007;//10^9+7
const LL INF2 = (LL)100000000000000000;//10^18


int main() {
	int n; cin >> n;

	string c; cin >> c;

	//1が羊
	//-1が狼

	vector<int> toggle(2);
	toggle[0] = 1;
	toggle[1] = -1;

	vector<int> circle(n);

	for (auto f : toggle) {
		for (auto s : toggle) {
			int left;

			if (f == 1) {
				if (c[0] == 'o') {
					left = s;
				}
				else {
					left = -s;
				}
			}
			else {
				if (c[0] == 'x') {
					left = s;
				}
				else {
					left = -s;
				}
			}

			circle[0] = f;
			circle[1] = s;

			for (int i = 1; i < n-1; i++) {
				int now = circle[i];

				if (now == 1) {
					if (c[i] == 'o') {
						circle[i + 1] = circle[i - 1];
					}
					else {
						circle[i + 1] = -circle[i - 1];
					}
				}
				else {
					if (c[i] == 'x') {
						circle[i + 1] = circle[i - 1];
					}
					else {
						circle[i + 1] = -circle[i - 1];
					}
				}
			}

			bool done = true;
			int last = circle[n - 1];

			if (last == 1) {
				if (c[n - 1] == 'o') {
					if (circle[0] != circle[n - 2]) {
						done = false;
					}
				}
				else {
					if (circle[0] == circle[n - 2]) {
						done = false;
					}
				}
			}
			else {
				if (c[n - 1] == 'o') {
					if (circle[0] == circle[n - 2]) {
						done = false;
					}
				}
				else {
					if (circle[0] != circle[n - 2]) {
						done = false;
					}

				}
			}

			int last = circle[0];

			if (last == 1) {
				if (c[0] == 'o') {
					if (circle[1] != circle[n - 1]) {
						done = false;
					}
				}
				else {
					if (circle[1] == circle[n - 1]) {
						done = false;
					}
				}
			}
			else {
				if (c[0] == 'o') {
					if (circle[1] == circle[n - 1]) {
						done = false;
					}
				}
				else {
					if (circle[1] != circle[n - 1]) {
						done = false;
					}

				}
			}

			for (int i = 1; i < n-1; i++) {
				int last = circle[i];

				if (last == 1) {
					if (c[i] == 'o') {
						if (circle[i+1] != circle[i-1]) {
							done = false;
						}
					}
					else {
						if (circle[i+1] == circle[i-1]) {
							done = false;
						}
					}
				}
				else {
					if (c[i] == 'o') {
						if (circle[i+1] == circle[i-1]) {
							done = false;
						}
					}
					else {
						if (circle[i+1] != circle[i-1]) {
							done = false;
						}

					}
				}
			}
			
			
			
			if (done) {
				for (int i = 0; i < n; i++) {
					if (circle[i] == 1) {
						cout << "S";
					}
					else {
						cout << "W";
					}
				}

				cout << endl;
				return 0;

			}
			
			
		}


	}

	cout << "-1" << endl;
		
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:159:29: error: redeclaration of 'int last'
  159 |                         int last = circle[0];
      |                             ^~~~
a.cc:131:29: note: 'int last' previously declared here
  131 |                         int last = circle[n - 1];
      |                             ^~~~