結果
| 問題 |
No.19 ステージの選択
|
| ユーザー |
 Oland
|
| 提出日時 | 2019-11-01 18:47:57 |
| 言語 | Java (openjdk 23) |
| 結果 |
AC
|
| 実行時間 | 57 ms / 5,000 ms |
| コード長 | 9,124 bytes |
| コンパイル時間 | 3,716 ms |
| コンパイル使用メモリ | 81,100 KB |
| 実行使用メモリ | 37,512 KB |
| 最終ジャッジ日時 | 2024-09-14 22:49:03 |
| 合計ジャッジ時間 | 5,075 ms |
|
ジャッジサーバーID （参考情報） |
judge3 / judge2 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| other | AC * 24 |
ソースコード
import java.io.*;
import java.util.*;
@SuppressWarnings("unused")
public class Main {
private FastScanner in;
private PrintWriter out;
final int MOD = (int)1e9+7;
long ceil(long a, long b){return (a + b - 1) / b;}
long gcd(long a, long b){return b == 0 ? a : gcd(b, a % b);}
long lcm(long a, long b){return a / gcd(a, b) * b; /*オーバーフローに注意*/}
void solve(){
int N = in.nextInt();
ArrayList<ArrayList<Integer>> g = new ArrayList<>();
for(int i = 0; i < N; i++) g.add(new ArrayList<>());
double[] L = new double[N];
for (int i = 0; i < N; i++) {
L[i] = in.nextDouble();
int S = in.nextInt()-1;
g.get(S).add(i);
}
StronglyConnectedComponents scc = new StronglyConnectedComponents(g);
boolean[] visited = new boolean[scc.size];
double ans = 0;
for(int i = 0; i < scc.size; i++){
double min = Double.MAX_VALUE, sum = 0;
for(int v : scc.vs.get(i)){
min = Math.min(min, L[v]);
sum += L[v];
}
if(!visited[i]) sum += min;
sum /= 2;
ans += sum;
for(int to : scc.cg.get(i)) visited[to] = true;
}
out.println(ans);
}
//end solve
static class StronglyConnectedComponents {
//size of contracted graph
int size;
//vertex's index in contracted graph
int[] comp;
//contracted graph, vertices that belong vertex of contracted graph
ArrayList<ArrayList<Integer>> cg, vs;
private ArrayList<ArrayList<Integer>> g, gg, rg;
private ArrayList<Integer> order;
private boolean[] used;
StronglyConnectedComponents(ArrayList<ArrayList<Integer>> g) {
this.g = g;
gg = new ArrayList<>();
rg = new ArrayList<>();
for(int i = 0; i < g.size(); i++) gg.add(new ArrayList<>());
for(int i = 0; i < g.size(); i++) rg.add(new ArrayList<>());
used = new boolean[g.size()];
comp = new int[g.size()];
Arrays.fill(comp, -1);
for(int from = 0; from < g.size(); from++){
for(int to : g.get(from)){
gg.get(from).add(to);
rg.get(to).add(from);
}
}
build();
buildGraph();
buildSets();
}
private void build(){
order = new ArrayList<>();
for (int i = 0; i < gg.size(); i++){
dfs(i);
}
Collections.reverse(order);
int ptr = 0;
for (int i : order){
if(comp[i] == -1){
reverseDfs(i, ptr);
ptr++;
}
}
size = ptr;
}
private void dfs(int idx) {
if(used[idx]) return;
used[idx] = true;
for (int to : gg.get(idx)) dfs(to);
order.add(idx);
}
private void reverseDfs(int idx, int cnt) {
if(comp[idx] != -1) return;
comp[idx] = cnt;
for (int to : rg.get(idx)) reverseDfs(to, cnt);
}
private void buildGraph(){
cg = new ArrayList<>();
for(int i = 0; i < size; i++) cg.add(new ArrayList<>());
for(int i = 0; i < g.size(); i++){
for(int to : g.get(i)){
int x = comp[i], y = comp[to];
if(x == y) continue;
cg.get(x).add(y);
}
}
}
private void buildSets(){
vs = new ArrayList<>();
for(int i = 0; i < size; i++) vs.add(new ArrayList<>());
for(int i = 0; i < g.size(); i++){
vs.get(comp[i]).add(i);
}
}
}
public static void main(String[] args) {
new Main().m();
}
private void m() {
in = new FastScanner(System.in);
out = new PrintWriter(System.out);
solve();
out.flush();
in.close();
out.close();
}
static class FastScanner {
private Reader input;
public FastScanner() {this(System.in);}
public FastScanner(InputStream stream) {this.input = new BufferedReader(new InputStreamReader(stream));}
public void close() {
try {
this.input.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public int nextInt() {return (int) nextLong();}
public long nextLong() {
try {
int sign = 1;
int b = input.read();
while ((b < '0' || '9' < b) && b != '-' && b != '+') {
b = input.read();
}
if (b == '-') {
sign = -1;
b = input.read();
} else if (b == '+') {
b = input.read();
}
long ret = b - '0';
while (true) {
b = input.read();
if (b < '0' || '9' < b) return ret * sign;
ret *= 10;
ret += b - '0';
}
} catch (IOException e) {
e.printStackTrace();
return -1;
}
}
public double nextDouble() {
try {
double sign = 1;
int b = input.read();
while ((b < '0' || '9' < b) && b != '-' && b != '+') {
b = input.read();
}
if (b == '-') {
sign = -1;
b = input.read();
} else if (b == '+') {
b = input.read();
}
double ret = b - '0';
while (true) {
b = input.read();
if (b < '0' || '9' < b) break;
ret *= 10;
ret += b - '0';
}
if (b != '.') return sign * ret;
double div = 1;
b = input.read();
while ('0' <= b && b <= '9') {
ret *= 10;
ret += b - '0';
div *= 10;
b = input.read();
}
return sign * ret / div;
} catch (IOException e) {
e.printStackTrace();
return Double.NaN;
}
}
public char nextChar() {
try {
int b = input.read();
while (Character.isWhitespace(b)) {
b = input.read();
}
return (char) b;
} catch (IOException e) {
e.printStackTrace();
return 0;
}
}
public String nextStr() {
try {
StringBuilder sb = new StringBuilder();
int b = input.read();
while (Character.isWhitespace(b)) {
b = input.read();
}
while (b != -1 && !Character.isWhitespace(b)) {
sb.append((char) b);
b = input.read();
}
return sb.toString();
} catch (IOException e) {
e.printStackTrace();
return "";
}
}
public int[] nextIntArray(int n) {
int[] res = new int[n];
for (int i = 0; i < n; i++) {
res[i] = nextInt();
}
return res;
}
public int[] nextIntArrayDec(int n) {
int[] res = new int[n];
for (int i = 0; i < n; i++) {
res[i] = nextInt() - 1;
}
return res;
}
public int[] nextIntArray1Index(int n) {
int[] res = new int[n + 1];
for (int i = 0; i < n; i++) {
res[i + 1] = nextInt();
}
return res;
}
public long[] nextLongArray(int n) {
long[] res = new long[n];
for (int i = 0; i < n; i++) {
res[i] = nextLong();
}
return res;
}
public long[] nextLongArrayDec(int n) {
long[] res = new long[n];
for (int i = 0; i < n; i++) {
res[i] = nextLong() - 1;
}
return res;
}
public long[] nextLongArray1Index(int n) {
long[] res = new long[n + 1];
for (int i = 0; i < n; i++) {
res[i + 1] = nextLong();
}
return res;
}
public double[] nextDoubleArray(int n) {
double[] res = new double[n];
for (int i = 0; i < n; i++) {
res[i] = nextDouble();
}
return res;
}
}
}