Submission #692355

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Source Code Expand

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.Comparator;
import java.util.InputMismatchException;
import java.util.List;
import java.util.PriorityQueue;

public class Main {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		int n = ni();
		int[] a = na(n);
		out.println(doHuTucker(a));
	}
	
	static class Datum
	{
		public int type;
		public int ind0, ind1;
		public long sum;
		public Datum(int type, int ind0, int ind1, long sum) {
			this.type = type;
			this.ind0 = ind0;
			this.ind1 = ind1;
			this.sum = sum;
		}
		@Override
		public String toString() {
			return "Datum [type=" + type + ", ind0=" + ind0 + ", ind1=" + ind1
					+ ", sum=" + sum + "]";
		}
	}
	
	public static long doHuTucker(int[] a)
	{
		int n = a.length;
		// [0, leaf-index, leaf-index, sum]
		// [1, leaf-index, inner-node-index, sum]
		// [2, inner-node-index, sum]
		int gen = n;
		PriorityQueue<Datum> pq = new PriorityQueue<Datum>(n, new Comparator<Datum>(){
			public int compare(Datum x, Datum y)
			{
				return Long.compare(x.sum, y.sum);
			}
		});
		boolean[] merged = new boolean[n];
		LST notMerged = new LST(n+1);
		notMerged.setRange(n+1);
		for(int i = 0;i < n-1;i++){
			pq.add(new Datum(0, i, i+1, (long)a[i]+a[i+1]));
		}
		// leaf    0 1 2 3 4
		// inner  0 1 2 3 4 5
		Node[] heaps = new Node[n+1];
		long ret = 0;
		while(gen < 2*n-1){
			Datum cur = pq.poll();
			int low = -1;
			if(cur.type == 0){
				if(merged[cur.ind0] || merged[cur.ind1])continue;
				merged[cur.ind0] = merged[cur.ind1] = true;
				notMerged.unset(cur.ind0+1);
				notMerged.unset(cur.ind1+1);
				low = notMerged.prev(cur.ind0+1);
				heaps[low] = merge(heaps[low], merge(heaps[cur.ind0+1], heaps[cur.ind1+1]));
				heaps[low] = merge(heaps[low], new Node(cur.sum));
				heaps[cur.ind0+1] = null;
				heaps[cur.ind1+1] = null;
			}else if(cur.type == 1){
				if(merged[cur.ind0])continue;
				if(heaps[cur.ind1] == null)continue;
				if(heaps[cur.ind1].val + a[cur.ind0] != cur.sum)continue;
				
				heaps[cur.ind1] = deleteRoot(heaps[cur.ind1]);
				
				merged[cur.ind0] = true;
				notMerged.unset(cur.ind0+1);
				low = notMerged.prev(cur.ind0+1);
				heaps[low] = merge(heaps[low], heaps[cur.ind0+1]);
				heaps[low] = merge(heaps[low], new Node(cur.sum));
				heaps[cur.ind0+1] = null;
			}else if(cur.type == 2){
				if(min2(heaps[cur.ind0]) == Long.MAX_VALUE)continue;
				if(min(heaps[cur.ind0]) + min2(heaps[cur.ind0]) != cur.sum)continue;
				
				Node min0 = heaps[cur.ind0];
				Node min1 = deleteRoot(heaps[cur.ind0]);
				
				heaps[cur.ind0] = deleteRoot(min1);
				heaps[cur.ind0] = merge(heaps[cur.ind0], new Node(cur.sum));
				low = cur.ind0;
			}
			int nex = notMerged.next(low+1);
			{
				long val = takeInner(heaps[low]);
				if(val != -1)pq.add(new Datum(2, low, -1, val));
			}
			if(low-1 != -1 && heaps[low] != null){
				pq.add(new Datum(1, low-1, low, a[low-1] + heaps[low].val));
			}
			if(nex != -1 && heaps[low] != null){
				pq.add(new Datum(1, nex-1, low, a[nex-1] + heaps[low].val));
			}
			if(low-1 != -1 && nex != -1){
				pq.add(new Datum(0, low-1, nex-1, (long)a[low-1] + a[nex-1]));
			}
			ret += cur.sum;
			gen++;
		}
		return ret;
	}
	
	static long takeInner(Node heap)
	{
		long min1 = min2(heap);
		if(min1 == Long.MAX_VALUE)return -1;
		return min(heap) + min1;
	}
	
	public static class Node
	{
		public long val;
		public Node left, right;
		public int dist;
		
		public Node(long x)
		{
			val = x;
			left = right = null;
			dist = 0;
		}
		
		public Node(Node n)
		{
			val = n.val;
			left = n.left;
			right = n.right;
			dist = n.dist;
		}
		
		public void disconnect()
		{
			left = right = null;
			dist = 0;
		}
		
		public String toString(String indent)
		{
			StringBuilder sb = new StringBuilder();
			if(left != null)sb.append(left.toString(indent + "  "));
			sb.append(indent).append(val).append('\n');
			if(right != null)sb.append(right.toString(indent + "  "));
			return sb.toString();
		}
	}
	
	public static Node merge(Node m, Node n)
	{
		if(m == null)return n;
		if(n == null)return m;
		if(m.val > n.val){ // compare
			Node d = m; m = n; n = d;
		}
		// m = new Node(m); // if uncommented, heap becomes persistent.
		m.right = merge(m.right, n);
		if(m.left == null || m.right.dist > m.left.dist){
			Node d = m.left; m.left = m.right; m.right = d;
		}
		m.dist = m.right == null ? 0 : m.right.dist + 1;
		return m;
	}
	
	public static long min(Node n)
	{
		return n != null ? n.val : Long.MAX_VALUE;
	}
	
	public static long min2(Node n)
	{
		if(n == null)return Long.MAX_VALUE;
		return Math.min(min(n.left), min(n.right));
	}
	
	public static Node deleteRoot(Node n){
		if(n == null)return null;
		Node ret = merge(n.left, n.right);
		n.disconnect();
		return ret;
	}
	
	public static class LST {
		public long[][] set;
		public int n;
//		public int size;
		
		public LST(int n) {
			this.n = n;
			int d = 1;
			for(int m = n;m > 1;m>>>=6, d++);
			
			set = new long[d][];
			for(int i = 0, m = n>>>6;i < d;i++, m>>>=6){
				set[i] = new long[m+1];
			}
//			size = 0;
		}
		
		// [0,r)
		public LST setRange(int r)
		{
			for(int i = 0;i < set.length;i++, r=r+63>>>6){
				for(int j = 0;j < r>>>6;j++){
					set[i][j] = -1L;
				}
				if((r&63) != 0)set[i][r>>>6] |= (1L<<r)-1;
			}
			return this;
		}
		
		// [0,r)
		public LST unsetRange(int r)
		{
			if(r >= 0){
				for(int i = 0;i < set.length;i++, r=r+63>>>6){
					for(int j = 0;j < r+63>>>6;j++){
						set[i][j] = 0;
					}
					if((r&63) != 0)set[i][r>>>6] &= ~((1L<<r)-1);
				}
			}
			return this;
		}
		
		public LST set(int pos)
		{
			if(pos >= 0 && pos < n){
//				if(!get(pos))size++;
				for(int i = 0;i < set.length;i++, pos>>>=6){
					set[i][pos>>>6] |= 1L<<pos;
				}
			}
			return this;
		}
		
		public LST unset(int pos)
		{
			if(pos >= 0 && pos < n){
//				if(get(pos))size--;
				for(int i = 0;i < set.length && (i == 0 || set[i-1][pos] == 0L);i++, pos>>>=6){
					set[i][pos>>>6] &= ~(1L<<pos);
				}
			}
			return this;
		}
		
		public boolean get(int pos)
		{
			return pos >= 0 && pos < n && set[0][pos>>>6]<<~pos<0;
		}
		
		public int prev(int pos)
		{
			for(int i = 0;i < set.length && pos >= 0;i++, pos>>>=6, pos--){
				int pre = prev(set[i][pos>>>6], pos&63);
				if(pre != -1){
					pos = pos>>>6<<6|pre;
					while(i > 0)pos = pos<<6|63-Long.numberOfLeadingZeros(set[--i][pos]);
					return pos;
				}
			}
			return -1;
		}
		
		public int next(int pos)
		{
			for(int i = 0;i < set.length && pos>>>6 < set[i].length;i++, pos>>>=6, pos++){
				int nex = next(set[i][pos>>>6], pos&63);
				if(nex != -1){
					pos = pos>>>6<<6|nex;
					while(i > 0)pos = pos<<6|Long.numberOfTrailingZeros(set[--i][pos]);
					return pos;
				}
			}
			return -1;
		}
		
		private static int prev(long set, int n)
		{
			long h = Long.highestOneBit(set<<~n);
			if(h == 0L)return -1;
			return Long.numberOfTrailingZeros(h)-(63-n);
		}
		
		private static int next(long set, int n)
		{
			long h = Long.lowestOneBit(set>>>n);
			if(h == 0L)return -1;
			return Long.numberOfTrailingZeros(h)+n;
		}
		
		@Override
		public String toString()
		{
			List<Integer> list = new ArrayList<Integer>();
			for(int pos = next(0);pos != -1;pos = next(pos+1)){
				list.add(pos);
			}
			return list.toString();
		}
	}
	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	private static boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
		
		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}
	
	private static byte[] inbuf = new byte[1024];
	static int lenbuf = 0, ptrbuf = 0;
	
	private static 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 static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
//	private static boolean isSpaceChar(int c) { return !(c >= 32 && c <= 126); }
	private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private static double nd() { return Double.parseDouble(ns()); }
	private static char nc() { return (char)skip(); }
	
	private static String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private static 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 static 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 static int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private static int ni()
	{
		int num = 0, 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 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) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}

Submission Info

Judge Result