#include <bits/stdc++.h> using namespace std; const int mxN = 100010; struct node { int w_count; int child[26]; }; int n; vector<string> s; vector<node> tree; vector<int> mark(mxN * 20); vector<char> answer; int id_max; int cnt = 0; void new_node() { node x; x.w_count = 0; for(int i = 0; i < 26; i ++) x.child[i] = -1; tree.push_back(x); } void init() { new_node(); } void add(string s, int type) { int idx = 0; for(int i = 0; i < s.size(); i ++) { int w = s[i] - 'a'; if(tree[idx].child[w] == -1) { new_node(); tree[idx].child[w] = tree.size() - 1; } idx = tree[idx].child[w]; mark[idx] = type; } tree[idx].w_count ++ ; } void _dfs(int u) { for(int i = 1; i <= tree[u].w_count; i ++) { answer.push_back('P'); cnt ++ ; } if(cnt == n) { cout << answer.size() << "\n"; for(auto c : answer) cout << c << "\n"; exit(0); } for(int i = 0; i < 26; i ++) { int v = tree[u].child[i]; if(v == -1) continue ; if(!mark[v]) { answer.push_back((char)(i + 'a')); _dfs(v); answer.push_back('-'); } } for(int i = 0; i < 26; i ++) { int v = tree[u].child[i]; if(v == -1) continue ; if(mark[v]) { answer.push_back((char)(i + 'a')); _dfs(v); answer.push_back('-'); } } } int main() { #define taskname "" if(fopen(taskname".inp", "r")) { freopen(taskname".inp", "r", stdin); freopen(taskname".out", "w", stdout); } cin.tie(0)->sync_with_stdio(0); cin >> n; s.resize(n + 1); init(); for(int i = 1; i <= n; i ++) { cin >> s[i]; if(s[i].size() > s[id_max].size()) { id_max = i; } } for(int i = 1; i <= n; i ++) { if(i == id_max) continue ; add(s[i], 0); } add(s[id_max], 1); _dfs(0); return 0; }

printer.cpp: In function 'void add(std::string, int)':
printer.cpp:32:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |     for(int i = 0; i < s.size(); i ++) {
      |                    ~~^~~~~~~~~~
printer.cpp: In function 'int main()':
printer.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
printer.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen(taskname".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~