LightOJ1010---Knights in chessboard (regular problem)

Given a m x n chessboard where you want to place chess Knights. You have to find the number of maximum knights so can be placed in the chessboard such that no, and Knights attack each O Ther.

Those who is not familiar with Chess knights, note this a chess knight can attack 8 positions in the board as shown in th e picture below.

Input

Input starts with an integer T (≤41000), denoting the number of test cases.

Each case contains the integers m, n (1≤m, n≤200). Here m and n corresponds to the number of rows and the number of columns of the board respectively.
Output

For each case, print the case number and maximum number of knights so can be placed in the board considering the above R Estrictions.
Sample Input

Output for Sample Input

3

8 8

3 7

4 10

Case 1:32

Case 2:11

Case 3:20

Problem Setter:jane Alam Jan

Regular questions
Assume n? m is even and is greater than 2
The answer is n? m / 2
Assuming that both N and M are odd and are greater than 2
And the answer is half the line. m / 2 + 1 and half of them. m/2 A
Assuming that N m is less than or equal to 2
N (m) is 1, the answer is M (n)

M (n) has a 2, then we can consider how many 2*2 lattice
With X, the answer is ( x / 2 + x % 2)? 4
The rest may have a 2*1, assuming that x is odd and cannot be placed, assuming that X is an even number that can be placed

/************************************************************************* > File Name:LightOJ1010.cpp > Author:alex > Mail: [email protected] > Created time:2015 June 08 Monday 14:24 24 seconds *************************** *********************************************/#include <functional>#include <algorithm>#include <iostream>#include <fstream>#include <cstring>#include <cstdio>#include <cmath>#include <cstdlib>#include <queue>#include <stack>#include <map>#include <bitset>#include <set>#include <vector>using namespace STD;Const DoublePI =ACOs(-1.0);Const intINF =0x3f3f3f3f;Const DoubleEPS =1e-15;typedef Long LongLL;typedefPair <int,int> PLL;intMain () {intT, Icase =1;scanf("%d", &t); while(t--) {intN, M;scanf("%d%d", &n, &m);intAns =0;if(N >=3&& m >=3) {if(n * M%2==0) {ans = n * M/2; }Else{ints = m/2+1; Ans + = (n/2+1) * s; Ans + = (n/2) * (S-1); }        }Else{if(n = =1) {ans = m; }Else if(M = =1) {ans = n; }Else{if(M = =2) {swap (n, m); }if(M <=3) {ans =4; }Else{intCNT = m/2; Ans = (CNT/2+ cnt%2) *4;if(M%2&& CNT%2==0) {ans + =2; }                }            }        }printf("Case%d:%d\n", icase++, ans); }return 0;}

LightOJ1010---Knights in chessboard (regular problem)