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ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#111090 | #6560. Broken Minimum Spanning Tree | KhNURE_KIVI# | WA | 2ms | 3520kb | C++20 | 3.6kb | 2023-06-05 19:53:32 | 2023-06-05 19:53:33 |
Judging History
answer
//#pragma GCC optimize("Ofast", "unroll-loops")
//#pragma GCC target("sse", "sse2", "sse3", "ssse3", "sse4")
#include <bits/stdc++.h>
#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define pb push_back
#define fir first
#define sec second
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;
template<typename T>
inline bool umin(T &a, T b) {
if (b < a) {
a = b;
return true;
}
return false;
}
template<typename T>
inline bool umax(T &a, T b) {
if (a < b) {
a = b;
return true;
}
return false;
}
#ifdef LOCAL
#define D for (bool _FLAG = true; _FLAG; _FLAG = false)
#define LOG(...) print(#__VA_ARGS__" ::", __VA_ARGS__) << endl
template <class ...Ts> auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }
#else
#define D while (false)
#define LOG(...)
#endif // LOCAL
const int max_n = 2023, inf = 1000111222;
struct edge {
int l, r, c, id;
bool operator < (const edge &x) const {
return c < x.c || c == x.c && id < x.id;
}
};
struct dsu {
public:
int n;
vector <int> p, cnt;
inline void make_set (int v) {
p[v] = v;
}
dsu (int n) : n(n) {
p.resize(n);
cnt.assign(n, 1);
for (int i = 0; i < n; i++) {
make_set(i);
}
}
inline int get (int v) {
if (p[v] == v) return v;
return p[v] = get(p[v]); /// compressing path
}
inline bool unite (int a, int b) {
a = get(a);
b = get(b);
if (a == b) return false;
if (cnt[a] > cnt[b]) {
swap(a, b);
}
p[a] = b;
cnt[b] += cnt[a];
return true;
}
};
set <pii> g[max_n];
vector <int> path;
inline bool get_path (int a, int b, int p = -1) {
if (a == b) {
return true;
}
for (auto &i : g[a]) {
if (i.first == p) {
continue;
}
path.pb(i.second);
if (get_path(i.first, b, a)) {
return true;
}
path.pop_back();
}
return false;
}
int main() {
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
vector <edge> e(m);
for (int i = 0; i < m; i++) {
cin >> e[i].l >> e[i].r >> e[i].c;
e[i].id = i;
--e[i].l;
--e[i].r;
g[e[i].l].insert({e[i].r, i});
g[e[i].r].insert({e[i].l, i});
}
auto E = e;
sort(all(e));
dsu t(n);
vector <edge> id;
vector <int> need(m);
for (int i = 0; i < m; i++) {
if (t.unite(e[i].l, e[i].r)) {
id.pb(e[i]);
need[e[i].id] = 1;
}
}
vector <pii> ans;
for (auto &i : id) {
if (i.id >= n - 1) {
path.clear();
get_path(i.l, i.r);
bool ok = false;
for (auto &j : path) {
if (!need[j]) {
ok = true;
ans.pb({j, i.id});
g[E[j].l].erase({E[j].r, E[j].id});
g[E[j].r].erase({E[j].l, E[j].id});
g[i.l].insert({i.r, i.id});
g[i.r].insert({i.l, i.id});
break;
}
}
assert(ok);
}
}
cout << len(ans) << '\n';
for (auto &i : ans) {
cout << i.first + 1 << ' ' << i.second + 1 << '\n';
}
}
詳細信息
Test #1:
score: 100
Accepted
time: 2ms
memory: 3516kb
input:
4 4 1 2 10 2 3 3 3 4 1 1 4 4
output:
1 1 4
result:
ok correct!
Test #2:
score: -100
Wrong Answer
time: 0ms
memory: 3520kb
input:
6 8 1 2 10 2 3 10 3 4 10 4 5 10 5 6 10 6 1 10 1 3 1 4 6 1
output:
2 2 7 6 8
result:
wrong answer bad swap 6 8