UVa 10783 Odd Sum (water ver.)

10783 - Odd Sum

Time limit: 3.000 seconds

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=19&page=show_problem&problem=1724

Given a range [a, b], you are to find the summation of all the odd integers in this range. For example, the summation of all the odd integers in the range [3, 9] is 3 + 5 + 7 + 9 = 24.

Input 

There can be at multiple test cases. The first line of input gives you the number of test cases, T ( 1T100). Then T test cases follow. Each test case consists of 2 integers a and b ( 0ab100) in two separate lines.

Output 

For each test case you are to print one line of output - the serial number of the test case followed by the summation of the odd integers in the range [a, b].

Sample Input 

21535

Sample Output 

Case 1: 9Case 2: 8

完整代码：

/*0.006s*/#include <cstdio>int main(void){int t, a, b;scanf("%d", &t);for (int i = 1; i <= t; ++i){scanf("%d%d", &a, &b);a >>= 1, b = (b + 1) >> 1;printf("Case %d: %d\n", i, b * b - a * a);}return 0;}