题解 | #牛牛的金币#

#include <stdio.h>
#include <math.h>

int main() {
    int x = 0;
    int y = 0;
    int x1 = 0;
    int y1 = 0;

    while (4 == scanf("%d %d %d %d", &x, &y, &x1, &y1))
    {
        if (abs(x1 - x) + abs(y1 - y) == 1)
        {
            if ((y1 - y) > 0)
            {
                printf("u");
            }
            else if ((y1 - y) < 0)
            {
                printf("d");
            }
            else if ((x1 - x) > 0)
            {
                printf("r");
            }
            else if ((x1 - x) < 0)
            {
                printf("l");
            }
            printf("\n");
        }
    }
    return 0;
}