九度OJ 1136：Number Steps（步数） （基础题）

时间限制：1 秒

内存限制：32 兆

特殊判题：否

提交：691

解决：412

题目描述：

Starting from point (0,0) on a plane, we have written all non-negative integers 0,1,2, ... as shown in the figure. For example, 1, 2, and 3 has been written at points (1,1), (2,0), and (3, 1) respectively
and this pattern has continued.

You are to write a program that reads the coordinates of a point (x, y), and writes the number (if any) that has been written at that point. (x, y) coordinates in the input are in the range 0...5000.

输入：

The first line of the input is N, the number of test cases for this problem. In each of the N following lines, there is x, and y representing the coordinates (x, y) of a point.

输出：

For each point in the input, write the number written at that point or write No Number if there is none.

样例输入：

3
4 2
6 6
3 4

样例输出：

6
12
No Number

来源：

2008年北京大学软件所计算机研究生机试真题

思路：

细节题，要分清各类情况。

代码：

#include <stdio.h>

int main(void)
{
    int n, i;
    int x, y;

    while (scanf("%d", &n) != EOF)
    {
        for(i=0; i<n; i++)
        {
            scanf("%d%d", &x, &y);
            if (x == y || x-y == 2)
            {
                if (x%2 == 0)
                    printf("%d\n", x+y);
                else
                    printf("%d\n", x+y-1);
            }
            else
                printf("No Number\n");
        }
    }

    return 0;
}
/**************************************************************
    Problem: 1136
    User: liangrx06
    Language: C
    Result: Accepted
    Time:20 ms
    Memory:912 kb
****************************************************************/