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
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 33
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ソースコード

diff #
プレゼンテーションモードにする

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)); }
}
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