hoge

nyan.c

#include <stdio.h>
#include <setjmp.h>

#define HEAP 5000
const int N = 10;

enum Tag {
    ask_depth,
    answer
};

struct tuple {
    int fst;
    enum Tag snd;
};

jmp_buf env;
int i,tag;
int* heap[HEAP];

int **top;

#define timetravel(v) ({                                        \
            if((tag = setjmp(env))==0){                         \
                for(i=0 ; i<HEAP; ++i)heap[i] = top[-i];        \
                return v;                                       \
            }                                                   \
            else{                                               \
                for(i=0 ; i<HEAP; ++i)top[-i] = heap[i];        \
            }                                                   \
            tag;                                                \
        })

struct tuple f(){
    const int v = timetravel(((struct tuple){1,ask_depth}));

    printf("now %d\n",v);

    if(v == N){
        return (struct tuple){v,answer};
    }
    else {
        const struct tuple p = f();
        if(p.snd == 0){
            return (struct tuple){p.fst + 1,ask_depth};
        }
        else{
            return (struct tuple){p.fst + v,answer};
        }
    }
}

int main()
{
    top = __builtin_frame_address(0);
    const struct tuple p = f();
    if(p.snd == ask_depth){
        longjmp(env,p.fst);
    }
    else{
        printf("sum = %d\n",p.fst);
    }
    return 0;
}