ZOJ 1414 Number Steps

Number Steps

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Time Limit: 2 Seconds      Memory Limit: 65536 KB

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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.

Input

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.

Output

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

Sample Input

3
4 2
6 6
3 4

Sample Output

6
12
No Number

题意：就是找规律只有x==y||x-y==2才存在，当x是偶数时，那个点是x+y,奇数时,那个点x+y-1

代码：

#include <stdio.h>


int main()
{
    int x,y;
    int N;
    scanf("%d",&N);
    
    while(N--)
    {
        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;
}