Gym - 101246A Bencoding【模拟】

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
const int maxn = 1e6+100;
const int inf = 0x7fffffff;
char a[maxn];
int len,ans;
long long m;
void sloveDict(int &i);
void sloveInt(int &i);
void sloveList(int &i);
void sloveString(int &i);

void sloveInt(int &i)
{
    m-=3;
    if(m<0)
        ans = min(i,ans);
    int num = -1;
    while(ans==inf && a[++i]!='e')
    {
        if(num!=0 && a[i]>='0' && a[i]<='9')
        {
            if(num==-1)
                num = a[i]-'0';
            else
                m--;
            if(m<0)
                ans = min(ans,i);
        }
        else
            ans = min(ans,i);
    }
    if(num==-1)
        ans = min(ans,i);
}
void sloveString(int &i)
{
    long long tlen = a[i]-'0';
    m -= tlen+2;
    if(m<0)
        ans = min(ans,i);
    while(ans==inf && a[++i]!=':')
    {
        if(tlen!=0 && a[i]>='0' && a[i]<='9')
        {
            m -= (tlen*10+a[i]-'0')+1 - tlen;
            tlen = tlen*10+a[i]-'0';
            if(m<0)
                ans = min(ans,i);
        }
        else
            ans = min(ans,i);
    }
    while(tlen&&i        i++,tlen--;
    if(i==len)
        ans = min(ans,i);
}
void sloveList(int &i)
{
    m -= 2;
    if(m<0)
        ans = min(ans,i);
    while(ans==inf&&a[++i]!='e')
    {
        if(a[i]=='l')
            sloveList(i);
        else if(a[i]=='d')
            sloveDict(i);
        else if(a[i]=='i')
            sloveInt(i);
        else if(a[i]<='9' && a[i]>='0')
            sloveString(i);
        else
            ans = min(i,ans);
    }
}
void sloveDict(int &i)
{
    m-=2;
    if(m<0)
        ans = min(i,ans);
    int num = 0;
    while(ans==inf && a[++i]!='e')
    {
        num^=1;
        if(num)
            m -= 2;
        else
            m += 2;
        if(a[i]=='l')
            sloveList(i);
        else if(a[i]=='d')
            sloveDict(i);
        else if(a[i]=='i')
            sloveInt(i);
        else if(a[i]<='9' && a[i]>='0')
            sloveString(i);
        else
            ans = min(i,ans);
    }
    if(num)
        ans = min(i,ans);
}
int main()
{
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    scanf("%I64d %s",&m,a);
    len = strlen(a);
    int i = 0;
    ans = inf;
    if(a[0]=='l')
        sloveList(i);
    else if(a[0]=='d')
        sloveDict(i);
    else if(a[0]=='i')
        sloveInt(i);
    else if(a[0]<='9' && a[0]>='0')
        sloveString(i);
    else
        ans = min(0,ans);
    i++;
    if(i        ans = min(i,ans);
    if(ans!=inf)
        printf("Error at position %d!\n",ans);
    else
        puts("ok");
    return 0;
}