ACM 101 The Blocks Problem

除了硬幹好像也沒別招了？
不過儲存資料的結構實在長的很噁心……
之前用2維陣列存，這次試著用結構存看看
本題可以練習到stack的運作方式。
之前ACM10038 free就被WA，
這次free就沒事 -_-。

/* ACM 101
 * mythnc
 * 2011/10/14 16:08:24   
 * run time: 0.008
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXARY 25

typedef struct robot {
    int *block;
    int count;
} Action;

void init(Action *[], int n);
int position(Action *[], int *, int);
void clear(Action *[], int *);
void move(Action *[], int *, int *);
void print(Action *[], int);

int main(void)
{
    /* a[3]: 0 for a, 1 for position a, 2 for block a */
    /* same as b */
    int n, a[3], b[3];
    char str1[MAXARY], str2[MAXARY];
    Action *arm[MAXARY];

    scanf("%d", &n);
    init(arm, n);
    while (scanf("%s %d %s %d", str1, a, str2, b) == 4) {
        if (a[0] == b[0])
            continue;
        if ((a[1]= position(arm, a, n)) ==
            (b[1]= position(arm, b, n)))
            continue;
        if (strcmp(str1, "move") == 0)
            clear(arm, a);
        if (strcmp(str2, "onto") == 0)
            clear(arm, b);
        move(arm, b, a);
    }
    print(arm, n);
    return 0;
}

/* init: initialize arm */
void init(Action *arm[], int n)
{
    int i;

    for (i = 0; i < n; i++) { /* initialize arm */
        arm[i] = (Action *)malloc(sizeof(Action));
        arm[i]->block = (int *)malloc(sizeof(int) * n);
        arm[i]->count = 0;
        arm[i]->block[arm[i]->count++] = i;
    }
}

/* position: return position and block of pt[0] */
int position(Action *arm[], int *pt, int n)
{
    int i, j;

    for (i = 0; i < n; i++)
        for (j = 0; j < arm[i]->count; j++)
            if (arm[i]->block[j] == pt[0]) {  /* position i, block j */
                pt[2] = j;
                return i;
            }
}

/* clear: clear blocks above x */
void clear(Action *arm[], int *x)
{
    int tmp;

    while (arm[x[1]]->count != x[2] + 1) {  /* return tmp to it's position */
        tmp = arm[x[1]]->block[--arm[x[1]]->count];
        arm[tmp]->block[arm[tmp]->count++] = tmp;
    }
}

/* move: move a to b */
void move(Action *arm[], int *b, int *a)
{
    int i;

    for (i = a[2]; i < arm[a[1]]->count; i++)
        arm[b[1]]->block[arm[b[1]]->count++] = arm[a[1]]->block[i];
    arm[a[1]]->count = a[2];
}

/* print: print out final state */
void print(Action *arm[], int n)
{
    int i, j;

    for (i = 0; i < n; i++) {
        printf("%d:", i);
        for (j = 0; j < arm[i]->count; j++)
            printf(" %d", arm[i]->block[j]);
        free(arm[i]->block);
        free(arm[i]);
        printf("\n");
    }
}