Bailian4006 little rabbit picks up gold coins [simulation]

4006: The little rabbit picked up gold coins

Total time limit : 1000ms Memory limit : 65536kB
describe
In a game , The little rabbit can pick up gold coins . It will pick up the passing gold coins while walking . When the little rabbit found that there were no gold coins ahead , Will automatically turn right . Until all the gold coins were picked up . Now put one NХN In the square area of , Gold coins are placed in each grid . Suppose the little rabbit starts from the first space on the top left , Go to the right . Here is the following ：

1 2 3 4
12 13 14 5
11 16 15 6
10 9 8 7

The second one I found k A gold coin will be marked k, It is recorded as the serial number of the gold coin . Then ask No i That's ok , The first j What is the serial number of the gold coins in the column ？ （1≤i≤N, 1≤j≤N）
Input
The first line has an integer K and N, N Indicates the size of the square area （1≤N≤10000）, and K Indicates the number of groups of input coordinates .（1≤K≤25）
And then there will be K That's ok , Each line has two integers separated by spaces i and j, Indicates the number of rows and columns of gold coins to be sought .
Output
Total output K That's ok . Each line outputs a serial number of gold coins in corresponding coordinates .
The sample input
3 4
1 3
2 2
3 3
Sample output
3
13
15

Question link ：Bailian4006 The little rabbit picked up gold coins
A brief description of the problem ：（ A little ）
Problem analysis ： Simulation question , Don't explain .
Program description ：（ A little ）
Reference link ：（ A little ）
. ：（ A little ）

AC Of C++ The language program is as follows ：

/* Bailian4006  The little rabbit picked up gold coins  */

#include <stdio.h>

#define N 10000
int c[N + 1];
int dx[4] = {
    0, 1, 0, -1};
int dy[4] = {
    1, 0, -1, 0};

int main()
{
    
    int k, n;
    scanf("%d%d", &k, &n);

    c[1] = 1;
    for (int i = 1, j = 1; i <= n / 2; i++, j += 2)
        c[i + 1] = c[i] + 4 * (n - j);

    for (int i = 1; i <= k; i++) {
    
        int row, col, row2, col2;
        scanf("%d%d", &row, &col);
        row2 = row, col2 = col;
        if (row2 > n / 2) row2 = n - row2 + 1;
        if (col2 > n / 2) col2 = n - col2 + 1;
        int t = row2 < col2 ? row2 : col2;
        int x = t, y = t, start = c[t], x2 = 0;
        while (start < c[t + 1]) {
    
            if (x == row && y == col) break;
            int nextx = x + dx[x2];
            int nexty = y + dy[x2];
            if (nextx >= t && nexty >= t && nextx <= n - t + 1 && nexty <= n - t + 1)
                x = nextx, y = nexty, start++;
            else
                {
    if (++x2 >= 4) x2 = 0;}
        }

        printf("%d\n", start);
    }

    return 0;
}