#define PROBLEM "https://judge.yosupo.jp/problem/shortest_path"
#include "../../cpp/template/template.cpp"
#include "../../cpp/graph/shortest-path/dijkstra.cpp"
int main(){
int n,m,s,t;cin>>n>>m>>s>>t;
dijkstra<long long> A(n);
for(int i = 0; m > i; i++){
int a,b;long long c;cin>>a>>b>>c;
A.push_side(a,b,c);
}
A.build(s);
if(A[t] == INF)cout << -1 << endl;
else{
auto R = A.restoration(t);
if(R[0] == -1){
cout << -1 << endl;
return 0;
}
cout << A[t] << " " << R.size()-1 << endl;
for(int i = 0; R.size()-1 > i; i++){
cout << R[i] << " " << R[i+1] << endl;
}
}
}
#line 1 "cpp/z_test/yosupo-shortest_path.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/shortest_path"
#line 2 "cpp/template/template.cpp"
//yukicoder@cpp17
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <cctype>
#include <climits>
#include <cassert>
#include <string>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>
#include <random>
#include <bitset>
#include <complex>
#include <utility>
#include <numeric>
#include <functional>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
const ll MOD = 998244353;
const ll MODx = 1000000007;
const int INF = (1<<30)-1;
const ll LINF = (1LL<<62LL)-1;
const double EPS = (1e-10);
P ar4[4] = {{0,1},{0,-1},{1,0},{-1,0}};
P ar8[8] = {{-1,-1},{-1,0},{-1,1},{0,-1},{0,1},{1,-1},{1,0},{1,1}};
template <typename T> vector<T> make_vector(size_t a, T b) { return vector<T>(a, b); }
template <typename... Ts> auto make_vector(size_t a, Ts... ts) { return vector<decltype(make_vector(ts...))>(a, make_vector(ts...)); }
/*
確認ポイント
cout << fixed << setprecision(n) << 小数計算//n桁の小数表記になる
計算量は変わらないが楽できるシリーズ
min(max)_element(iter,iter)で一番小さい(大きい)値のポインタが帰ってくる
count(iter,iter,int)でintがiterからiterの間にいくつあったかを取得できる
*/
/* comment outed because can cause bugs
__attribute__((constructor))
void initial() {
cin.tie(0);
ios::sync_with_stdio(false);
}
*/
#line 4 "cpp/z_test/yosupo-shortest_path.test.cpp"
#line 1 "cpp/graph/shortest-path/dijkstra.cpp"
template<typename T>
class dijkstra{
struct vg{
int t;
T c;
};
vector<pair<int,T>> cost;
int beg = -1;
void run(int x){
auto comp = [](vg a,vg b){
return a.c>b.c;
};
priority_queue<vg,vector<vg>,decltype(comp)> R{comp};
for(int i = 0; n > i; i++){
cost[i].second = -1;
}
cost[x].first = -1;
cost[x].second = 0;
R.push({x,0});
while(R.size()){
auto k = R.top();R.pop();
if(cost[k.t].second != k.c)continue;
for(int i = 0; A[k.t].size() > i; i++){
if(cost[A[k.t][i].t].second != -1 && cost[A[k.t][i].t].second <= k.c+A[k.t][i].c)continue;
cost[A[k.t][i].t].second = k.c+A[k.t][i].c;
cost[A[k.t][i].t].first = k.t;
R.push({A[k.t][i].t,k.c+A[k.t][i].c});
}
}
}
public:
int n;
vector<vector<vg>> A;
vector<vector<vg>> Rev;
dijkstra(int n_):n(n_),A(n_),Rev(n_),cost(n_,{-1,-1}){}
//双方向
void push(int s,int v,T c){
A[s].push_back({v,c});
A[v].push_back({s,c});
Rev[s].push_back({v,c});
Rev[v].push_back({s,c});
}
void push_side(int s,int v,T c){
A[s].push_back({v,c});
Rev[v].push_back({s,c});
}
void build(int x){
run(x);
beg = x;
}
//restorate any
vector<int> restoration(int t = -1){
vector<int> Ret;
if(beg == -1 || (t != -1 && cost[t].second == -1)){
Ret.push_back(-1);
return Ret;
}
int ind = t;
if(ind == -1){
T tmp = cost[0].second;
int tmpin = 0;
for(int i = 0; n > i; i++){
if(tmp < cost[i].second){
tmp = cost[i].second;
tmpin = i;
}
}
ind = tmpin;
}
Ret.push_back(ind);
while(beg != ind){
Ret.push_back({cost[ind].first});
ind = cost[ind].first;
}
reverse(Ret.begin(),Ret.end());
return Ret;
}
T operator[](int i){
return cost[i].second;
}
};
#line 6 "cpp/z_test/yosupo-shortest_path.test.cpp"
int main(){
int n,m,s,t;cin>>n>>m>>s>>t;
dijkstra<long long> A(n);
for(int i = 0; m > i; i++){
int a,b;long long c;cin>>a>>b>>c;
A.push_side(a,b,c);
}
A.build(s);
if(A[t] == INF)cout << -1 << endl;
else{
auto R = A.restoration(t);
if(R[0] == -1){
cout << -1 << endl;
return 0;
}
cout << A[t] << " " << R.size()-1 << endl;
for(int i = 0; R.size()-1 > i; i++){
cout << R[i] << " " << R[i+1] << endl;
}
}
}
cpp/z_test/yosupo-shortest_path.test.cpp
cpp/geometry/two-points-distance.cpp