Problem Link ~~~~~ // package Quarantine;
import java.io.*; import java.util.Arrays; import java.util.StringTokenizer;
public class Present { static class Reader { final private int BUFFER_SIZE = 1 << 16; private DataInputStream din; private byte[] buffer; private int bufferPointer, bytesRead;
public Reader() { din = new DataInputStream(System.in); buffer = new byte[BUFFER_SIZE]; bufferPointer = bytesRead = 0; } public Reader(String file_name) throws IOException { din = new DataInputStream(new FileInputStream(file_name)); buffer = new byte[BUFFER_SIZE]; bufferPointer = bytesRead = 0; } public String readLine() throws IOException { byte[] buf = new byte[64]; // line length int cnt = 0, c; while ((c = read()) != -1) { if (c == '\n') break; buf[cnt++] = (byte) c; } return new String(buf, 0, cnt); } public int nextInt() throws IOException { int ret = 0; byte c = read(); while (c <= ' ') c = read(); boolean neg = (c == '-'); if (neg) c = read(); do { ret = ret * 10 + c - '0'; } while ((c = read()) >= '0' && c <= '9'); if (neg) return -ret; return ret; } public long nextLong() throws IOException { long ret = 0; byte c = read(); while (c <= ' ') c = read(); boolean neg = (c == '-'); if (neg) c = read(); do { ret = ret * 10 + c - '0'; } while ((c = read()) >= '0' && c <= '9'); if (neg) return -ret; return ret; } public double nextDouble() throws IOException { double ret = 0, div = 1; byte c = read(); while (c <= ' ') c = read(); boolean neg = (c == '-'); if (neg) c = read(); do { ret = ret * 10 + c - '0'; } while ((c = read()) >= '0' && c <= '9'); if (c == '.') { while ((c = read()) >= '0' && c <= '9') { ret += (c - '0') / (div *= 10); } } if (neg) return -ret; return ret; } private void fillBuffer() throws IOException { bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); if (bytesRead == -1) buffer[0] = -1; } private byte read() throws IOException { if (bufferPointer == bytesRead) fillBuffer(); return buffer[bufferPointer++]; } public void close() throws IOException { if (din == null) return; din.close(); } } public static void main(String[] args)throws IOException { Reader s=new Reader(); int n=s.nextInt(); int a[]=new int[n+1]; for(int i=1;i<=n;i++){ a[i]=s.nextInt(); } int ans=0; for(int i=0;i<=25;i++){ int b[]=getArray(a,i); Arrays.sort(b); long count=getCount(b,n,i); if(count%2!=0){ ans|=1<<i; } } System.out.println(ans); } public static int[] getArray(int a[],int k){ int b[]=new int[a.length]; int t=1<<(k+1); for(int i=1;i<a.length;i++){ b[i]=a[i]%t; } return b; } public static long getCount(int b[],int n,int k){ long ans=0; int left1=1<<k; int right1=1<<(k+1); int left2=(1 << k) + (1 << (k + 1)); int right2=1 << (k + 2) - 1; int x=n+1; for(int i=1;i<=n;i++){ int rc=getInd(b,i,n,left1); if(rc==x){ continue; } int lc=getInd(b,i,n,right1); ans+=lc-rc; if(k!=0) { rc = getInd(b, i, n, left2); if(rc==x){ continue; } lc = getInd(b, i, n, right2); ans += lc - rc; } } return ans; } public static int getInd(int a[],int ind,int n,int reqd){ int num=a[ind]; int low=ind+1; int high=n; int ans=n+1; while(low<=high){ int mid=(low+high)/2; if(a[mid]+num>=reqd){ ans=mid; high=mid-1; } else{ low=mid+1; } } return ans; }
}
~~~~~