Submission #2497104

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Source Code Expand

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
char s[50005];
int root,last,sz,ch[50005][26],fa[50005],sum[50005],l[50005];
int n,m,b[50005],cnt[50005];
void extend(int x) 
{
    int c=s[x]-'a';
    int p=last,np=++sz; last=np;
    l[np]=x+1;
    for (;p&&!ch[p][c];p=fa[p]) ch[p][c]=np;
    if (!p) fa[np]=root;
    else 
    {
        int q=ch[p][c];
        if (l[p]+1==l[q]) fa[np]=q;
        else 
        {
            int nq=++sz; l[nq]=l[p]+1;
            memcpy(ch[nq],ch[q],sizeof(ch[q]));
            fa[nq]=fa[q]; fa[np]=fa[q]=nq;
            for (;p&&q==ch[p][c];p=fa[p]) ch[p][c]=nq;
        }
    }
}
void calc() 
{
    for (int i=1; i<=sz; i++) cnt[l[i]]++;
    for (int i=1; i<=n; i++) cnt[i]+=cnt[i-1];
    for (int i=1; i<=sz; i++) b[cnt[l[i]]--]=i;
    for (int i=sz; i; i--) 
    {
        int p=b[i]; sum[p]=1;
        for (int j=0; j<26; j++) sum[p]+=sum[ch[p][j]];
    }
}

int main() 
{
    scanf("%s",s);
    n=strlen(s);
    root=last=++sz;
    for (int i=0; i<n; i++) extend(i);
    calc();
    int x,p=root; 
    scanf("%d",&x);
    while (x) 
    {
        for (int c=0; c<26; c++)
            if(ch[p][c]) 
            {
                if(sum[ch[p][c]]>=x) 
                {
                    putchar(c+'a');
                    x--; p=ch[p][c];
                    break;
                }
                else x-=sum[ch[p][c]];
            }
    }
    puts("");
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:42:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s",s);
                  ^
./Main.cpp:48:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&x);
                   ^

Judge Result