#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto& a : x)
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define sz(x) (int)x.size()
#define beg(x) x.begin()
#define en(x) x.end()
#define all(x) beg(x), en(x)
#define resz resize
const int MOD = 1000000007; // 998244353
const ll INF = 1e18;
const int MX = 100001;
const ld PI = 4*atan((ld)1);
template<class T> void ckmin(T &a, T b) { a = min(a, b); }
template<class T> void ckmax(T &a, T b) { a = max(a, b); }
template<class A, class B> A operator+=(A& l, const B& r) { return l = l+r; }
template<class A, class B> A operator-=(A& l, const B& r) { return l = l-r; }
template<class A, class B> A operator*=(A& l, const B& r) { return l = l*r; }
template<class A, class B> A operator/=(A& l, const B& r) { return l = l/r; }
namespace input {
template<class T> void re(complex<T>& x);
template<class T1, class T2> void re(pair<T1,T2>& p);
template<class T> void re(vector<T>& a);
template<class T, size_t SZ> void re(array<T,SZ>& a);
template<class T> void re(T& x) { cin >> x; }
void re(double& x) { string t; re(t); x = stod(t); }
void re(ld& x) { string t; re(t); x = stold(t); }
template<class Arg, class... Args> void re(Arg& first, Args&... rest) {
re(first); re(rest...);
}
template<class T> void re(complex<T>& x) { T a,b; re(a,b); x = cd(a,b); }
template<class T1, class T2> void re(pair<T1,T2>& p) { re(p.f,p.s); }
template<class T> void re(vector<T>& a) { F0R(i,sz(a)) re(a[i]); }
template<class T, size_t SZ> void re(array<T,SZ>& a) { F0R(i,SZ) re(a[i]); }
}
using namespace input;
namespace output {
template<class T1, class T2> void pr(const pair<T1,T2>& x);
template<class T, size_t SZ> void pr(const array<T,SZ>& x);
template<class T> void pr(const vector<T>& x);
template<class T> void pr(const set<T>& x);
template<class T1, class T2> void pr(const map<T1,T2>& x);
template<class T> void pr(const T& x) { cout << x; }
template<class Arg, class... Args> void pr(const Arg& first, const Args&... rest) {
pr(first); pr(rest...);
}
template<class T1, class T2> void pr(const pair<T1,T2>& x) {
pr("{",x.f,", ",x.s,"}");
}
template<class T> void prContain(const T& x) {
pr("{");
bool fst = 1; trav(a,x) pr(!fst?", ":"",a), fst = 0;
pr("}");
}
template<class T, size_t SZ> void pr(const array<T,SZ>& x) { prContain(x); }
template<class T> void pr(const vector<T>& x) { prContain(x); }
template<class T> void pr(const set<T>& x) { prContain(x); }
template<class T1, class T2> void pr(const map<T1,T2>& x) { prContain(x); }
void ps() { pr("\n"); }
template<class Arg, class... Args> void ps(const Arg& first, const Args&... rest) {
pr(first," "); ps(rest...); // print w/ spaces
}
}
using namespace output;
namespace io {
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
void setIO(string s = "") {
ios_base::sync_with_stdio(0); cin.tie(0); // fast I/O
if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}
}
using namespace io;
template<class T> T invGeneral(T a, T b) {
a %= b; if (a == 0) return b == 1 ? 0 : -1;
T x = invGeneral(b,a);
return x == -1 ? -1 : ((1-(ll)b*x)/a+b)%b;
}
template<class T> struct modInt {
T val;
T mod = 0;
// static const T mod = MOD;
void normalize() {
if (mod == 0) return;
val %= mod; if (val < 0) val += mod;
}
modInt(T v = 0, T m = 0) : val(v), mod(m) { normalize(); }
// modInt(T v = 0, T m = 0) : val(v) { normalize(); }
explicit operator T() const { return val; }
friend ostream& operator<<(ostream& os, const modInt& a) { return os << a.val; }
friend bool operator==(const modInt& a, const modInt& b) { return a.val == b.val; }
friend bool operator!=(const modInt& a, const modInt& b) { return !(a == b); }
friend void check(modInt& a, modInt& b) { // make sure all operations are valid
// comment out if mod is static const
if (a.mod > 0 && b.mod > 0) { assert(a.mod == b.mod); return; }
T mod = max(a.mod,b.mod); if (mod == 0) mod = MOD;
if (a.mod != mod) { a.mod = mod; a.normalize(); }
if (b.mod != mod) { b.mod = mod; b.normalize(); }
}
friend modInt operator+(modInt a, modInt b) {
check(a,b); a.val += (T)b;
if (a.val >= a.mod) a.val -= a.mod;
return a;
}
friend modInt operator-(modInt a, modInt b) {
check(a,b); a.val -= (T)b;
if (a.val < 0) a.val += a.mod;
return a;
}
friend modInt operator-(const modInt& a) { return modInt(0)-a; }
friend modInt operator*(modInt a, modInt b) {
check(a,b); a.val = (ll)a.val*(T)b%a.mod; return a;
}
friend modInt exp(modInt a, ll p) {
modInt ans(1,a.mod);
for (; p; p /= 2, a *= a) if (p&1) ans *= a;
return ans;
}
friend modInt inv(const modInt& a) {
return {invGeneral(a.val,a.mod),a.mod};
// return exp(b,b.mod-2) if prime
}
friend modInt operator/(modInt a, modInt b) {
check(a,b); return a*inv(b);
}
};
typedef modInt<int> mi;
typedef pair<mi,mi> pmi;
typedef vector<mi> vmi;
typedef vector<pmi> vpmi;
int N,M;
template<int SZ> struct DSU {
int par[SZ], sz[SZ];
DSU() {
F0R(i,SZ) par[i] = i, sz[i] = 1;
}
int get(int x) { // path compression
if (par[x] != x) par[x] = get(par[x]);
return par[x];
}
bool unite(int x, int y) { // union-by-rank
x = get(x), y = get(y);
if (x == y) return 0;
if (sz[x] < sz[y]) swap(x,y);
sz[x] += sz[y], par[y] = x;
return 1;
}
};
DSU<MX> D;
vpi adj[MX];
int val[MX];
vector<array<int,4>> extra;
void dfs(int a, int b) {
trav(t,adj[a]) if (t.f != b) {
val[t.f] = val[a]^t.s;
dfs(t.f,a);
}
}
int main() {
setIO(); re(N,M);
F0R(i,M) {
int a,b,p; re(a,b,p);
if (D.unite(a,b)) adj[a].pb({b,p}), adj[b].pb({a,p});
else extra.pb({a,b,p,i+1});
}
dfs(1,0);
vpi v;
trav(t,extra) v.pb({t[2]^val[t[0]]^val[t[1]],t[3]});
// ps(v);
vector<vi> res;
F0Rd(i,31) {
int ind = 0; while (ind < sz(v) && (!(v[ind].f&(1<<i)))) ind ++;
if (ind == sz(v)) continue;
int t = v[ind].f;
vi todo;
trav(j,v) if (j.f > (j.f^t)) {
j.f ^= t;
todo.pb(j.s);
}
todo.insert(todo.begin(),sz(todo));
todo.insert(todo.begin(),t);
res.pb(todo);
}
ps(sz(res));
trav(t,res) {
trav(x,t) pr(x," ");
ps();
}
}
/* stuff you should look for
* int overflow, array bounds
* special cases (n=1?), set tle
* do smth instead of nothing and stay organized
*/
Compilation message
parkticni.cpp: In function 'void io::setIn(std::__cxx11::string)':
parkticni.cpp:117:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
~~~~~~~^~~~~~~~~~~~~~~~~~~~~
parkticni.cpp: In function 'void io::setOut(std::__cxx11::string)':
parkticni.cpp:118:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
31 ms |
6260 KB |
Output is correct |
| 2 |
Correct |
38 ms |
6520 KB |
Output is correct |
| 3 |
Correct |
15 ms |
4248 KB |
Output is correct |
| 4 |
Correct |
10 ms |
4096 KB |
Output is correct |
| 5 |
Correct |
90 ms |
10488 KB |
Output is correct |
| 6 |
Correct |
158 ms |
10360 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
15 ms |
4732 KB |
Output is correct |
| 2 |
Correct |
17 ms |
4860 KB |
Output is correct |
| 3 |
Correct |
36 ms |
5208 KB |
Output is correct |
| 4 |
Correct |
31 ms |
5628 KB |
Output is correct |
| 5 |
Correct |
69 ms |
8688 KB |
Output is correct |
| 6 |
Correct |
43 ms |
6740 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
54 ms |
7256 KB |
Output is correct |
| 2 |
Correct |
75 ms |
8468 KB |
Output is correct |
| 3 |
Correct |
7 ms |
3456 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
75 ms |
8820 KB |
Output is correct |
| 2 |
Correct |
99 ms |
12524 KB |
Output is correct |
| 3 |
Correct |
6 ms |
3584 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
69 ms |
7796 KB |
Output is correct |
| 2 |
Correct |
70 ms |
8768 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
68 ms |
9964 KB |
Output is correct |
| 2 |
Correct |
35 ms |
6904 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
95 ms |
9720 KB |
Output is correct |
| 2 |
Correct |
78 ms |
11500 KB |
Output is correct |
| 3 |
Correct |
59 ms |
8568 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
115 ms |
12528 KB |
Output is correct |
| 2 |
Correct |
115 ms |
15084 KB |
Output is correct |
| 3 |
Correct |
110 ms |
13544 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
27 ms |
5504 KB |
Output is correct |
| 2 |
Correct |
43 ms |
6136 KB |
Output is correct |
| 3 |
Correct |
80 ms |
10228 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
80 ms |
10336 KB |
Output is correct |
| 2 |
Correct |
57 ms |
7544 KB |
Output is correct |
| 3 |
Correct |
115 ms |
12652 KB |
Output is correct |
