結果

問題 No.1254 補強への架け橋
ユーザー 草苺奶昔
提出日時 2023-02-13 02:24:05
言語 Go
(1.23.4)
結果
AC  
実行時間 222 ms / 2,000 ms
コード長 4,215 bytes
コンパイル時間 14,246 ms
コンパイル使用メモリ 233,680 KB
実行使用メモリ 45,264 KB
最終ジャッジ日時 2024-07-16 08:19:17
合計ジャッジ時間 26,933 ms
ジャッジサーバーID
(参考情報)
judge1 / judge3
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 123
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

package main
import (
"bufio"
"fmt"
"os"
"sort"
)
// int main() {
// int N;
// cin >> N;
// NamoriGraph< int > g(N);
// g.read(N);
// g.build();
// vector< int > ans;
// for(auto &e : g.loop_edges) {
// ans.emplace_back(e.idx + 1);
// }
// sort(begin(ans), end(ans));
// cout << ans.size() << "\n";
// cout << ans << "\n";
// }
func main() {
const INF int = int(1e18)
const MOD int = 998244353
in := bufio.NewReader(os.Stdin)
out := bufio.NewWriter(os.Stdout)
defer out.Flush()
var n int
fmt.Fscan(in, &n)
g := make([][]Edge, n)
for i := 0; i < n; i++ {
var a, b int
fmt.Fscan(in, &a, &b)
a--
b--
g[a] = append(g[a], Edge{a, b, 1, i})
g[b] = append(g[b], Edge{b, a, 1, i})
}
ng := NewNamoriGraph(g)
ng.Build()
res := []int{}
for _, e := range ng.LoopEdges {
res = append(res, e.index+1)
}
sort.Ints(res)
fmt.Fprintln(out, len(res))
for _, v := range res {
fmt.Fprint(out, v, " ")
}
}
type Edge = struct{ from, to, cost, index int }
type Graph = [][]Edge
type NamoriGraph struct {
Forest []Graph
LoopEdges []Edge
g Graph
iv [][]int
markId, id []int
}
func NewNamoriGraph(g Graph) *NamoriGraph {
return &NamoriGraph{g: g}
}
func (ng *NamoriGraph) Build() {
n := len(ng.g)
deg := make([]int, n)
used := make([]bool, n)
que := []int{}
for i := 0; i < n; i++ {
deg[i] = len(ng.g[i])
if deg[i] == 1 {
que = append(que, i)
used[i] = true
}
}
for len(que) > 0 {
idx := que[0]
que = que[1:]
for _, e := range ng.g[idx] {
if used[e.to] {
continue
}
deg[e.to]--
if deg[e.to] == 1 {
que = append(que, e.to)
used[e.to] = true
}
}
}
mx := 0
for _, edges := range ng.g {
for _, e := range edges {
mx = max(mx, e.index)
}
}
edgeUsed := make([]bool, mx+1)
loop := []int{}
for i := 0; i < n; i++ {
if used[i] {
continue
}
for update := true; update; {
update = false
loop = append(loop, i)
for _, e := range ng.g[i] {
if used[e.to] || edgeUsed[e.index] {
continue
}
edgeUsed[e.index] = true
ng.LoopEdges = append(ng.LoopEdges, Edge{i, e.to, e.cost, e.index})
i = e.to
update = true
break
}
}
break
}
loop = loop[:len(loop)-1]
ng.markId = make([]int, n)
ng.id = make([]int, n)
for i := 0; i < len(loop); i++ {
pre := loop[(i+len(loop)-1)%len(loop)]
nxt := loop[(i+1)%len(loop)]
sz := 0
ng.markId[loop[i]] = i
ng.iv = append(ng.iv, []int{})
ng.id[loop[i]] = sz
sz++
ng.iv[len(ng.iv)-1] = append(ng.iv[len(ng.iv)-1], loop[i])
for _, e := range ng.g[loop[i]] {
if e.to != pre && e.to != nxt {
ng.markDfs(e.to, loop[i], i, &sz)
}
}
tree := make(Graph, sz)
for _, e := range ng.g[loop[i]] {
if e.to != pre && e.to != nxt {
tree[ng.id[loop[i]]] = append(tree[ng.id[loop[i]]], Edge{ng.id[loop[i]], ng.id[e.to], e.cost, e.index})
tree[ng.id[e.to]] = append(tree[ng.id[e.to]], Edge{ng.id[e.to], ng.id[loop[i]], e.cost, e.index})
ng.buildDfs(e.to, loop[i], tree)
}
}
ng.Forest = append(ng.Forest, tree)
}
}
// k, tree_id, id
func (ng *NamoriGraph) GetId(k int) (treeId, id int) {
return ng.markId[k], ng.id[k]
}
// tree_id k``
// GetInvId(tree_id, 0)
func (ng *NamoriGraph) GetInvId(treeId, k int) int {
return ng.iv[treeId][k]
}
// markDfs
func (ng *NamoriGraph) markDfs(idx, par, k int, l *int) {
ng.markId[idx] = k
ng.id[idx] = *l
*l++
ng.iv[len(ng.iv)-1] = append(ng.iv[len(ng.iv)-1], idx)
for _, e := range ng.g[idx] {
if e.to != par {
ng.markDfs(e.to, idx, k, l)
}
}
}
// buildDfs
func (ng *NamoriGraph) buildDfs(idx, par int, tree Graph) {
for _, e := range ng.g[idx] {
if e.to != par {
tree[ng.id[idx]] = append(tree[ng.id[idx]], Edge{ng.id[idx], ng.id[e.to], e.cost, e.index})
tree[ng.id[e.to]] = append(tree[ng.id[e.to]], Edge{ng.id[e.to], ng.id[idx], e.cost, e.index})
ng.buildDfs(e.to, idx, tree)
}
}
}
func max(a, b int) int {
if a > b {
return a
}
return b
}
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