Solution of LIGHT OJ 1133 :: Array Simulation

Before seeing the solution make sure that you tried enough. Don’t paste the whole code, just find out the logic. If you stuck in trouble, just inform me on comment.

/**Bismillahir Rahmanir Rahim.**/

#include <stdio.h>
int main()
{
    int tst, i;
    scanf("%d", &tst);
    for(i=1; i<=tst; i++)
    {
        int n, m, D;
        scanf("%d%d", &n, &m);
        int ara[n], j, k, l, tmp, x, y;
        for(j=0; j<n; j++)
            scanf("%d", &ara[j]);
        for(k=0; k<m; k++)
        {
            char step[2];
            scanf("%s", step);
            if(step[0]=='S')
            {
                scanf("%d", &D);
                for(j=0; j<n; j++)
                    ara[j]+=D;
            }
            else if(step[0]=='M')
            {
                scanf("%d", &D);
                for(j=0; j<n; j++)
                    ara[j]*=D;
            }
            else if(step[0]=='D')
            {
                scanf("%d", &D);
                for(j=0; j<n; j++)
                    ara[j]/=D;
            }
            else if(step[0]=='R')
            {
                for(j=0,l=n-1; j<n/2; j++, l--)
                {
                    tmp = ara[j];
                    ara[j] = ara[l];
                    ara[l] = tmp;
                }
            }
            else if(step[0]=='P')
            {
                scanf("%d%d", &x, &y);
                tmp = ara[x];
                ara[x] = ara[y];
                ara[y] = tmp;
            }
        }
        printf("Case %d:\n", i);
        for(j=0; j<n-1; j++)
            printf("%d ", ara[j]);
        printf("%d\n", ara[j]);
    }
    return 0;
}