結果
| 問題 | No.904 サメトロ |
| ユーザー |
 uwi
|
| 提出日時 | 2019-10-11 21:54:05 |
| 言語 | Java (openjdk 23) |
| 結果 |
AC
|
| 実行時間 | 52 ms / 1,000 ms |
| コード長 | 8,225 bytes |
| コンパイル時間 | 3,777 ms |
| コンパイル使用メモリ | 90,228 KB |
| 実行使用メモリ | 50,260 KB |
| 最終ジャッジ日時 | 2024-11-25 07:18:35 |
| 合計ジャッジ時間 | 6,415 ms |
|
ジャッジサーバーID （参考情報） |
judge5 / judge1 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 33 |
ソースコード
package contest1910;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.List;
public class B {
InputStream is;
PrintWriter out;
String INPUT = "";
void solve()
{
int n = ni();
int[] a = new int[n-1];
int[] b = new int[n-1];
for(int i = 0;i < n-1;i++) {
a[i] = ni();
b[i] = ni();
}
List<Edge> es = new ArrayList<>();
int src = 2*(n-1), sink = src + 1;
long lsum = 0, rsum = 0;
for(int i = 0;i < n-1;i++) {
lsum += a[i];
rsum += b[i];
es.add(new Edge(src, i, a[i]));
es.add(new Edge(i+n-1, sink, b[i]));
}
for(int i = 0;i < n-1;i++) {
for(int j = 0;j < n-1;j++) {
if(i != j) {
es.add(new Edge(i, j+n-1, 99999));
}
}
}
long F = maximumFlowDinicNoRec(compileWD(sink+1, es), src, sink);
out.println(F + 1);
}
public static class Edge
{
public int from, to;
public long capacity;
public long flow;
public Edge complement;
public boolean cloned;
public Edge(int from, int to, long capacity) {
this.from = from;
this.to = to;
this.capacity = capacity;
}
}
public static void reset(Edge[][] g)
{
for(Edge[] row : g){
for(Edge e : row){
e.flow = e.cloned ? e.capacity : 0;
}
}
}
public static Edge[][] compileWD(int n, List<Edge> edges)
{
Edge[][] g = new Edge[n][];
// cloning
for(int i = edges.size()-1;i >= 0;i--){
Edge origin = edges.get(i);
Edge clone = new Edge(origin.to, origin.from, origin.capacity);
clone.flow = origin.capacity;
clone.complement = origin;
clone.cloned = true;
origin.complement = clone;
edges.add(clone);
}
int[] p = new int[n];
for(Edge e : edges)p[e.from]++;
for(int i = 0;i < n;i++)g[i] = new Edge[p[i]];
for(Edge e : edges)g[e.from][--p[e.from]] = e;
return g;
}
public static Edge[][] compileWU(int n, List<Edge> edges)
{
Edge[][] g = new Edge[n][];
// cloning
for(int i = edges.size()-1;i >= 0;i--){
Edge origin = edges.get(i);
Edge clone = new Edge(origin.to, origin.from, origin.capacity*2);
origin.flow = origin.capacity;
clone.flow = origin.capacity;
clone.complement = origin;
clone.cloned = true;
origin.complement = clone;
origin.capacity *= 2;
edges.add(clone);
}
int[] p = new int[n];
for(Edge e : edges)p[e.from]++;
for(int i = 0;i < n;i++)g[i] = new Edge[p[i]];
for(Edge e : edges)g[e.from][--p[e.from]] = e;
return g;
}
public static long maximumFlowDinic(Edge[][] g, int source, int sink)
{
int n = g.length;
int[] d = new int[n];
int[] q = new int[n];
long ret = 0;
while(true){
Arrays.fill(d, -1);
q[0] = source;
int r = 1;
d[source] = 0;
for(int v = 0;v < r;v++){
int cur = q[v];
for(Edge ne : g[cur]){
if(d[ne.to] == -1 && ne.capacity - ne.flow > 0) {
q[r++] = ne.to;
d[ne.to] = d[cur] + 1;
}
}
}
if(d[sink] == -1)break;
int[] sp = new int[n];
for(int i = 0;i < n;i++)sp[i] = g[i].length - 1;
ret += dfsDinic(d, g, sp, source, sink, Long.MAX_VALUE);
}
return ret;
}
private static long dfsDinic(int[] d, Edge[][] g, int[] sp, int cur, int sink, long min)
{
if(cur == sink)return min;
long left = min;
for(int i = sp[cur];i >= 0;i--){
Edge ne = g[cur][i];
if(d[ne.to] == d[cur]+1 && ne.capacity - ne.flow > 0){
long fl = dfsDinic(d, g, sp, ne.to, sink, Math.min(left, ne.capacity - ne.flow));
if(fl > 0){
left -= fl;
ne.flow += fl;
ne.complement.flow -= fl;
if(left == 0){
sp[cur] = i;
return min;
}
}
}
}
sp[cur] = -1;
return min-left;
}
public static long maximumFlowDinicNoRec(Edge[][] g, int source, int sink)
{
int n = g.length;
int[] d = new int[n]; // distance
int[] q = new int[n]; // queue for BFS
long ret = 0;
int[] stack = new int[n];
long[] lefts = new long[n]; // left to flow
long[] parflow = new long[n];
int[] probe = new int[n]; // search pointer
while(true){
// BFS
Arrays.fill(d, -1);
q[0] = source;
int r = 1;
d[source] = 0;
for(int v = 0;v < r;v++){
int cur = q[v];
for(Edge ne : g[cur]){
if(d[ne.to] == -1 && ne.capacity - ne.flow > 0) {
q[r++] = ne.to;
d[ne.to] = d[cur] + 1;
}
}
}
if(d[sink] == -1)break;
// DFS
for(int i = 0;i < n;i++)probe[i] = g[i].length-1;
int sp = 0;
stack[sp] = source;
lefts[sp] = Long.MAX_VALUE / 10;
parflow[sp] = 0;
sp++;
long delta = 0;
boolean down = true;
while(sp > 0){
int cur = stack[sp-1];
long left = lefts[sp-1];
if(cur == sink){
delta += left;
parflow[sp-1] = left;
sp--;
down = false;
continue;
}
if(!down){
if(parflow[sp] > 0){
lefts[sp-1] -= parflow[sp];
left = lefts[sp-1];
Edge ne = g[cur][probe[cur]];
ne.flow += parflow[sp];
ne.complement.flow -= parflow[sp];
parflow[sp-1] += parflow[sp];
}
if(left > 0)probe[cur]--;
}
if(left > 0 && probe[cur] >= 0){
down = true;
Edge ne = g[cur][probe[cur]];
if(d[ne.to] == d[cur]+1 && ne.capacity - ne.flow > 0){
lefts[sp] = Math.min(left, ne.capacity - ne.flow);
stack[sp] = ne.to;
parflow[sp] = 0;
sp++;
}else{
probe[cur]--;
}
}else{
down = false;
sp--;
}
}
ret += delta;
}
return ret;
}
void run() throws Exception
{
is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
out = new PrintWriter(System.out);
long s = System.currentTimeMillis();
solve();
out.flush();
if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
// Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
// @Override
// public void run() {
// long s = System.currentTimeMillis();
// solve();
// out.flush();
// if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
// }
// };
// t.start();
// t.join();
}
public static void main(String[] args) throws Exception { new B().run(); }
private byte[] inbuf = new byte[1024];
public int lenbuf = 0, ptrbuf = 0;
private int readByte()
{
if(lenbuf == -1)throw new InputMismatchException();
if(ptrbuf >= lenbuf){
ptrbuf = 0;
try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
if(lenbuf <= 0)return -1;
}
return inbuf[ptrbuf++];
}
private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
private double nd() { return Double.parseDouble(ns()); }
private char nc() { return (char)skip(); }
private String ns()
{
int b = skip();
StringBuilder sb = new StringBuilder();
while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
private char[] ns(int n)
{
char[] buf = new char[n];
int b = skip(), p = 0;
while(p < n && !(isSpaceChar(b))){
buf[p++] = (char)b;
b = readByte();
}
return n == p ? buf : Arrays.copyOf(buf, p);
}
private int[] na(int n)
{
int[] a = new int[n];
for(int i = 0;i < n;i++)a[i] = ni();
return a;
}
private long[] nal(int n)
{
long[] a = new long[n];
for(int i = 0;i < n;i++)a[i] = nl();
return a;
}
private char[][] nm(int n, int m) {
char[][] map = new char[n][];
for(int i = 0;i < n;i++)map[i] = ns(m);
return map;
}
private int[][] nmi(int n, int m) {
int[][] map = new int[n][];
for(int i = 0;i < n;i++)map[i] = na(m);
return map;
}
private int ni() { return (int)nl(); }
private long nl()
{
long num = 0;
int b;
boolean minus = false;
while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
if(b == '-'){
minus = true;
b = readByte();
}
while(true){
if(b >= '0' && b <= '9'){
num = num * 10 + (b - '0');
}else{
return minus ? -num : num;
}
b = readByte();
}
}
private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}