uva 11044(数学)

题目：

The Loch Ness Monsterisa mysterious and unidentified animal said to inhabit Loch Ness, 
a large deep freshwaterloch near the cityof Inverness in northern Scotland. Nessie is usually categorized as a type oflake monster.
http://en.wikipedia.org/wiki/Loch_Ness_Monster

In July 2003, the BBC reported an extensive investigation of Loch Ness by a BBCteam, using 600 separate sonar beams, found no trace of any ¨sea monster¨(i.e., any large animal, known or unknown) in the loch. The BBC team concludedthat Nessie does not exist. Now we want to repeat the experiment.

Given a grid of n rows and m columns representing the loch, 6n, m10000, find the minimum number s

• one sonar occupies one position in the grid; the sonar beam controls its own cell and the contiguous cells;
• the border cells do not need to be controlled, because Nessy cannot hide there (she is too big).

For example,

$\textstyle \parbox{.5\textwidth}{\begin{center}\mbox{}\epsfbox{p11044.eps}\end{center}}$

where X represents a sonar, and the shaded cells are controlled bytheir sonar beams; the last figure gives us a solution.

input

The first line of the input contains an integer, t, indicating the number of test cases. For eachtest case, there is a line with two numbers separated by blanks, 6n, m10000, that is, the size of the grid (n rows and m columns).

output

For each test case, the output should consist of one line showing the minimumnumber of sonars that verifies the conditions above.

sample input

3
6 6
7 7
9 13

sample output

4
4
12

题解：边缘的格子不用算，找规律。

#include <iostream>
#include <cstdio>
using namespace std;

int main() {
	int t, m, n, ans;
	scanf("%d", &t);
	while (t--) {
		scanf("%d%d", &m, &n);
		if ((m - 2) % 3 == 0)
			m = (m - 2) / 3;
		else
			m = (m - 2) / 3 + 1;
		if ((n - 2) % 3 == 0)
			n = (n - 2) / 3;
		else
			n = (n - 2) / 3 + 1;
		ans = m * n;
		printf("%d\n", ans);
	}
}