2nd Phase EPY Coding Challenge 2004 (1st place)

/*
USER: leomaster@in.gr
LANG: C
TASK: dimokritos
*/
#include <stdio.h>
#include <stdlib.h>

int gps[1403][1403],*lntd,*lttd;
FILE *iostr;

int main() {
    int ps,dgt,mvs,vnx,vny;
    iostr = fopen("dimokritos.in", "r");
    fscanf(iostr, "%d", &dgt);
    lntd = (int *) malloc(dgt * sizeof (int));
    lttd = (int *) malloc(dgt * sizeof (int));
    for (ps = 0; ps < dgt; ps++) {
        fscanf(iostr, "%d %d", &lntd[ps], &lttd[ps]);
    }
    vnx = vny = 701;
    fscanf(iostr, "%d\n", &mvs);
    for (ps = 0; ps <= mvs; ps++) {
        if (ps > 0) {
            switch (getc(iostr)) {
                case 'U': vny++; break;
                case 'D': vny--; break;
                case 'R': vnx++; break;
                case 'L': vnx--; break;
            }
        }
        gps[vnx-1][vny-1]++; gps[vnx][vny]++; gps[vnx+1][vny+1]++;
        gps[vnx][vny-1]++; gps[vnx+1][vny]++; gps[vnx-1][vny+1]++;
        gps[vnx+1][vny-1]++; gps[vnx-1][vny]++; gps[vnx][vny+1]++;
    }
    fclose(iostr);
    iostr = fopen("dimokritos.out", "w");
    if (mvs > 0) {
        for (ps = 0; ps < dgt; ps++)
            if (gps[lntd[ps]+701][lttd[ps]+701] > 0)
                fprintf(iostr, "%d %d\n", ps+1, gps[ps[lntd]+701][ps[lttd]+701]);
    } else {
        fprintf(iostr, "-1\n");
    }
    fclose(iostr);
    free(lntd), free(lttd);
    return 0;
}