2015 Anhui Province race B. Summation

Title Description

For positive integer n,k, we define such a function F, which satisfies the following law

Now for N and k, your task is to calculate the value of f (n,k) .

Input

The first is an integer t, which indicates that there is a T group of data next to each group of data is N and K (1<=n,k<=108)

Output

Prints the value of f (n,k), one row for each output

Sample input3 1 1 2 1 3 1Sample output-1 1-2
Find the rules.

1#include <iostream>2#include <stdio.h>3 intMain ()4 {5     using namespacestd;6     Long Longc,i,j=1, m,n,t=0, rankl=0;7     intA;8scanf"%d",&a);9      while(SCANF ("%lld%lld", &m,&n)! =EOF) {Ten         if(m==1&&n==1) {printf ("-1\n");} One         Else{ Ac=m/(2*n); -rankl=n*c*N; -          for(i=2*n*c+1; i<=m;i++) the         { -t++; -             if(t>N) -             { +J + +; -t=1; +             } A             if((j+2)%2==0) at             { -rankl=rankl+i; -             } -             Else -             { -rankl=rankl-i; in             } -         } toprintf"%lld\n", RANKL); +t=0; rankl=0; j=1; -     }} the     return 0; * } $ /**************************************************************Panax Notoginseng problem:1206 - user:2014217052 the language:c++ + Result: Correct A time:614 Ms the memory:1504 KB + ****************************************************************/

2015 Anhui Province race B. Summation