UVa10025-The ? 1 ? 2 ? ... ? n = k problem

 1 import java.math.BigInteger;
 2 import java.util.Scanner;
 3 public class Main {
 4     static long l,r,mid; 
 5     public static long Binary(long k){
 6         l=0;r=100000;
 7         long ans=0;
 8         while(l<=r){
 9             mid=(l+r)/2;
10             long sum=mid*(mid+1)/2;
11             if(sum>=k){
12                 ans=mid;
13                 r=mid-1;
14             }
15             else{
16                 l=mid+1;
17             }
18         }
19         return ans;
20     }
21     public static long fun(long k){
22         if(k==0)
23             return 3;
24         long ans=Binary(k);
25         long sum=ans*(ans+1)/2;
26         if(k%2!=0){
27             for(long i=ans;i>=0;i--){
28                 long s=i*(i+1)/2;
29                 if(s<k)break;
30                 if(s%2!=0)
31                     return i;
32             }
33             for(long i=ans;;i++){
34                 long s=i*(i+1)/2;
35                 if(s%2!=0)
36                     return i;
37             }
38         }
39         else{
40             for(long i=ans;i>=0;i--){
41                 long s=i*(i+1)/2;
42                 if(s<k)break;
43                 if(s%2==0)
44                     return i;
45             }
46             for(long i=ans;;i++){
47                 long s=i*(i+1)/2;
48                 if(s%2==0)
49                     return i;
50             }
51         }
52     }
53     public static void main(String args[]){
54         Scanner cin=new Scanner(System.in);
55         int n;
56         n=cin.nextInt();
57         for(int i=0;i<n;i++){
58             long k;
59             k=cin.nextInt();
60             if(k<0)
61                 k=-k;
62             long ans=fun(k);
63             if(i!=0)
64                 System.out.println();
65             System.out.println(ans);
66         }
67     }
68 }