SPOJ: LPS – Longest Palindromic Substring

0

Problem Link : http://www.spoj.com/problems/LPS/


Solution Idea:
——————
This one is the straight forward implementation of manachar’s algorithm. You can learn about manachar algorithm form the following links-
1. Hackerearth’s Note
2. Hackerank Topic
3. Youtube


#include <bits/stdc++.h>

#define pii              pair <int,int>
#define pll              pair <long long,long long>
#define sc               scanf
#define pf               printf
#define Pi               2*acos(0.0)
#define ms(a,b)          memset(a, b, sizeof(a))
#define pb(a)            push_back(a)
#define MP               make_pair
#define db               double
#define ll               long long
#define EPS              10E-10
#define ff               first
#define ss               second
#define sqr(x)           (x)*(x)
#define D(x)             cout<<#x " = "<<(x)<<endl
#define VI               vector <int>
#define DBG              pf("Hi\n")
#define MOD              1000000007
#define CIN              ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define SZ(a)            (int)a.size()
#define sf(a)            scanf("%d",&a)
#define sfl(a)           scanf("%lld",&a)
#define sff(a,b)         scanf("%d %d",&a,&b)
#define sffl(a,b)        scanf("%lld %lld",&a,&b)
#define sfff(a,b,c)      scanf("%d %d %d",&a,&b,&c)
#define sfffl(a,b,c)     scanf("%lld %lld %lld",&a,&b,&c)
#define stlloop(v)       for(__typeof(v.begin()) it=v.begin();it!=v.end();it++)
#define loop(i,n)        for(int i=0;i<n;i++)
#define loop1(i,n)       for(int i=1;i<=n;i++)
#define REP(i,a,b)       for(int i=a;i<b;i++)
#define RREP(i,a,b)      for(int i=a;i>=b;i--)
#define TEST_CASE(t)     for(int z=1;z<=t;z++)
#define PRINT_CASE       printf("Case %d: ",z)
#define LINE_PRINT_CASE  printf("Case %d:\n",z)
#define CASE_PRINT       cout<<"Case "<<z<<": "
#define all(a)           a.begin(),a.end()
#define intlim           2147483648
#define infinity         (1<<28)
#define ull              unsigned long long
#define gcd(a, b)        __gcd(a, b)
#define lcm(a, b)        ((a)*((b)/gcd(a,b)))

using namespace std;


/*----------------------Graph Moves----------------*/
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*------------------------------------------------*/

/*-----------------------Bitmask------------------*/
//int Set(int N,int pos){return N=N | (1<<pos);}
//int reset(int N,int pos){return N= N & ~(1<<pos);}
//bool check(int N,int pos){return (bool)(N & (1<<pos));}
/*------------------------------------------------*/

#define mx 600005

char s1[mx];
int p[mx];
int n;

string process(string &str)
{
    string ret;
    ret+='$';
    ret+='#';
    for(int i=0;i<SZ(str);i++)
    {
       ret+=str[i];
       ret+='#';
    }
    ret+='@';
    return ret;
//    cout<<str<<endl;
}

int manacher(string &str)
{
    int c=0,r=0;
    for(int i=1;i<SZ(str)-1;i++)
    {
        int miror=c+c-i;
        if(i<r)
            p[i]=min(p[miror],r-i);
        while(str[i+1+p[i]]==str[i-1-p[i]])
            p[i]++;
        if(i+p[i]>r)
        {
            c=i;
            r=i+p[i];
        }
    }
    int ret=0;
    for(int i=0;i<SZ(str);i++)
        ret=max(ret,p[i]);
    return ret;
}

int main()
{

//    freopen("in.txt","r",stdin);
//	  freopen("out.txt","w",stdout);

      string str;

      scanf("%d",&n);
      scanf("%s",s1);

      str=s1;
      str=process(str);
      int ans=manacher(str);
      printf("%d\n",ans);

    return 0;
}



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Light OJ: 1255 – Substring Frequency(Hash)

0

Problem Link : http://lightoj.com:81/volume/problem/1255


#include <bits/stdc++.h>

#define pii              pair <int,int>
#define pll              pair <long long,long long>
#define sc               scanf
#define pf               printf
#define Pi               2*acos(0.0)
#define ms(a,b)          memset(a, b, sizeof(a))
#define pb(a)            push_back(a)
#define MP               make_pair
#define db               double
#define ll               long long
#define EPS              10E-10
#define ff               first
#define ss               second
#define sqr(x)           (x)*(x)
#define D(x)             cout<<#x " = "<<(x)<<endl
#define VI               vector <int>
#define DBG              pf("Hi\n")
#define MOD              1000000007
#define CIN              ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define SZ(a)            (int)a.size()
#define sf(a)            scanf("%d",&a)
#define sfl(a)           scanf("%lld",&a)
#define sff(a,b)         scanf("%d %d",&a,&b)
#define sffl(a,b)        scanf("%lld %lld",&a,&b)
#define sfff(a,b,c)      scanf("%d %d %d",&a,&b,&c)
#define sfffl(a,b,c)     scanf("%lld %lld %lld",&a,&b,&c)
#define stlloop(v)       for(__typeof(v.begin()) it=v.begin();it!=v.end();it++)
#define loop(i,n)        for(int i=0;i<n;i++)
#define loop1(i,n)       for(int i=1;i<=n;i++)
#define REP(i,a,b)       for(int i=a;i<b;i++)
#define RREP(i,a,b)      for(int i=a;i>=b;i--)
#define TEST_CASE(t)     for(int z=1;z<=t;z++)
#define PRINT_CASE       printf("Case %d: ",z)
#define CASE_PRINT       cout<<"Case "<<z<<": "
#define all(a)           a.begin(),a.end()
#define intlim           2147483648
#define infinity         (1<<28)
#define ull              unsigned long long
#define gcd(a, b)        __gcd(a, b)
#define lcm(a, b)        ((a)*((b)/gcd(a,b)))

using namespace std;


/*----------------------Graph Moves----------------*/
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*------------------------------------------------*/

/*-----------------------Bitmask------------------*/
//int Set(int N,int pos){return N=N | (1<<pos);}
//int reset(int N,int pos){return N= N & ~(1<<pos);}
//bool check(int N,int pos){return (bool)(N & (1<<pos));}
/*------------------------------------------------*/

/*---------------------Hashing---------------------*/

#define MH 1000006

#define Base1 10000019
#define Base2 10000079

#define MOD1 1000000007
#define MOD2 1000000009

ll B1[MH],B2[MH];

void init_hash()
{
    B1[0]=B2[0]=1;
    for(int i=1;i<MH;i++)
    {
        B1[i]=(B1[i-1]*Base1)%MOD1;
        B2[i]=(B2[i-1]*Base2)%MOD2;
    }
}

struct Hash
{
    pll H[MH];
    int digit[MH];
    int len;

    Hash()
    {
        len=0;
        H[0]=pll(0,0);
    }

    void clear()
    {
        len=0;
        H[0]=pll(0,0);
    }

    void insert(char ch)
    {
        len++;
        digit[len]=ch-'a'+1;
        H[len].ff=(((H[len-1].ff*Base1)%MOD1)+digit[len])%MOD1;
        H[len].ss=(((H[len-1].ss*Base2)%MOD2)+digit[len])%MOD2;
    }

    pll substr(int l, int r)
    {
        int sub_len=r-l+1;
        pll ans;
        ans.ff=(H[r].ff-((H[l-1].ff*B1[sub_len])%MOD1)+MOD1)%MOD1;
        ans.ss=(H[r].ss-((H[l-1].ss*B2[sub_len])%MOD2)+MOD2)%MOD2;
        return ans;
    }

    pll concate(pll h, int l, int r)
    {
        pll x=substr(l,r);
        int sub_len=r-l+1;
        h.ff=(((h.ff*B1[sub_len])%MOD1)+x.ff)%MOD1;
        h.ss=(((h.ss*B2[sub_len])%MOD2)+x.ss)%MOD2;
        return h;
    }

    bool operator==(const Hash& p) const
    {
        return len==p.len && H[len]==p.H[len];
    }

    pll & operator[](int index)
    {
        return H[index];
    }
};

Hash h1,h2;

int lcp(int id1, int id2, int l)
{
    int lo=1,hi=l;
    while(lo<=hi)
    {
        int mid=(lo+hi)/2;
        if(h1.substr(id1,id1+mid)==h2.substr(id2,id2+mid))
            lo=mid+1;
        else
            hi=mid-1;
    }
    return hi;
}

/*------------------Hashing End---------- ----------*/

char text[MH],pattern[MH];

int main()
{

    ///freopen("in.txt","r",stdin);
    ///freopen("out.txt","w",stdout);

    init_hash();
    int t;
    sf(t);
    getchar();

    TEST_CASE(t)
    {
        sc("%s %s",text,pattern);
        int l1=strlen(text);
        int l2=strlen(pattern);

        h1.clear();
        h2.clear();

        for(int i=0;i<l1;i++)
            h1.insert(text[i]);
        for(int i=0;i<l2;i++)
            h2.insert(pattern[i]);
        int ans=0;

        for(int i=0;i<=l1-l2;i++)
        {
            if(h1.substr(i+1,i+l2)==h2[l2])
                ans++;
        }

        PRINT_CASE;
        pf("%d\n",ans);


    }

    return 0;
}


UVa 11734 – Big Number of Teams will Solve This

0

Problem Link : https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=2834


/*
         +-+ +-+ +-+
         |R| |.| |S|
         +-+ +-+ +-+
*/

#include <bits/stdc++.h>

#define pii             pair <int,int>
#define sc              scanf
#define pf              printf
#define Pi              2*acos(0.0)
#define ms(a,b)         memset(a, b, sizeof(a))
#define pb(a)           push_back(a)
#define MP              make_pair
#define db              double
#define ll              long long
#define EPS             10E-10
#define ff              first
#define ss              second
#define sqr(x)          (x)*(x)
#define D(x)            cout<<#x " = "<<(x)<<endl
#define VI              vector <int>
#define DBG             pf("Hi\n")
#define MOD             100007
#define MAX             10000
#define CIN             ios_base::sync_with_stdio(0); cin.tie(0)
#define SZ(a)           (int)a.size()
#define sf(a)           scanf("%d",&a)
#define sfl(a)          scanf("%lld",&a)
#define sff(a,b)        scanf("%d %d",&a,&b)
#define sffl(a,b)       scanf("%lld %lld",&a,&b)
#define sfff(a,b,c)     scanf("%d %d %d",&a,&b,&c)
#define sfffl(a,b,c)    scanf("%lld %lld %lld",&a,&b,&c)
#define loop(i,n)       for(int i=0;i<n;i++)
#define REP(i,a,b)      for(int i=a;i<b;i++)
#define TEST_CASE(t)    for(int z=1;z<=t;z++)
#define PRINT_CASE      printf("Case %d: ",z)
#define CASE_PRINT      cout<<"Case "<<z<<": "
#define all(a)          a.begin(),a.end()
#define intlim          2147483648
#define inf             1000000
#define ull             unsigned long long

using namespace std;


/*----------------------Graph Moves----------------*/
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*------------------------------------------------*/

/*-----------------------Bitmask------------------*/
//int Set(int N,int pos){return N=N | (1<<pos);}
//int reset(int N,int pos){return N= N & ~(1<<pos);}
//bool check(int N,int pos){return (bool)(N & (1<<pos));}
/*------------------------------------------------*/



int main()
{
    ///freopen("in.txt","r",stdin);
    ///freopen("out.txt","w",stdout);
    int t;
    cin>>t;
    getchar();
    TEST_CASE(t)
    {
        string s1,s2;
        getline(cin,s1);
        getline(cin,s2);

        CASE_PRINT;

        if(s1==s2)
        {
            cout<<"Yes"<<endl;
        }
        else
        {
            string s3;
            loop(i,SZ(s1))
            {
                if(s1[i]!=' ')
                    s3+=s1[i];
            }
            if(s3==s2)
                cout<<"Output Format Error"<<endl;
            else
                cout<<"Wrong Answer"<<endl;
        }

    }
    return 0;
}

UVa 11734 – Big Number of Teams will Solve This

0

/*
User ID: turing_13
Link: http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=2834
*/

#include <bits/stdc++.h>

#define ll long long
#define sc scanf
#define pf printf
#define Pi 2*acos(0.0)

using namespace std;

int main()
{
    ///freopen("input.txt","r",stdin);
    ///freopen("output.txt","w",stdout);

    long long t;
    cin>>t;
    getchar();
    for(int i=1;i<=t;i++)
    {
        char str1[1000],str2[1000],str3[1000];
        gets(str1);
        gets(str2);
        if(!(strcmp(str1,str2)))
           {
               cout<<"Case "<<i<<": Yes"<<endl;
               continue;
           }
        int l=strlen(str1),k=0;
        for(int j=0;j<l;j++)
        {
            if(str1[j]!=' ')
               {
                   str3[k]=str1[j];
                   k++;
               }
        }
        str3[k]='\0';

        if(!(strcmp(str2,str3)))
            cout<<"Case "<<i<<": Output Format Error"<<endl;
        else
            cout<<"Case "<<i<<": Wrong Answer"<<endl;
    }
    return 0;
}