HDU 5769 Substring

正文索引 [隐藏]

Problem Description
Input
Output
Sample Input
Sample Output
Hint
题解
代码

Problem Description

?? is practicing his program skill, and now he is given a string, he has to calculate the total number of its distinct substrings.
But ?? thinks that is too easy, he wants to make this problem more interesting.
?? likes a character X very much, so he wants to know the number of distinct substrings which contains at least one X.
However, ?? is unable to solve it, please help him.

Input

The first line of the input gives the number of test cases T;T test cases follow.
Each test case is consist of 2 lines:
First line is a character X, and second line is a string S.
X is a lowercase letter, and S contains lowercase letters(‘a’-‘z’) only.
T<=30
1<=|S|<=10^5
The sum of |S| in all the test cases is no more than 700,000.

Output

For each test case, output one line containing “Case #x: y”(without quotes), where x is the test case number(starting from 1) and y is the answer you get for that case.

Sample Input

2
a
abc
b
bbb

Sample Output

Case #1: 3
Case #2: 3

Hint

In first case, all distinct substrings containing at least one a: a, ab, abc.
In second case, all distinct substrings containing at least one b: b, bb, bbb.

题解

见 http://bestcoder.hdu.edu.cn/blog/2016-multi-university-training-contest-4-solutions-by-fzu/ 的 1006

代码

/*
  Author : WNJXYK
  Problem : HDU 5769
  Blog : http://wnjxyk.cn
  Date : 2016.7.30
*/
#include<cstdio>
#include<cstdlib>
#include<ctime>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<set>
#include<vector>
#include<map>
using namespace std;
const int Maxn=100000;
inline void radix(int str[],int pos[],int sa[],int n,int m){
    static int cnt[Maxn+5];
    memset(cnt,0,sizeof(cnt));
    for (int i=0;i<n;i++) cnt[str[pos[i]]]++;
    for (int i=1;i<=m;i++) cnt[i]+=cnt[i-1];
    for (int i=n-1;i>=0;i--) sa[--cnt[str[pos[i]]]]=pos[i];
}
int sa[Maxn+5];
inline void SA(int str[],int sa[],int n,int m){
    static int rnk[Maxn+5],a[Maxn+5],b[Maxn+5];
    for (int i=0;i<n;i++) rnk[i]=i;
    radix(str,rnk,sa,n,m);
    rnk[sa[0]]=0;
    for (int i=1;i<n;i++)
        rnk[sa[i]] = rnk[sa[i-1]] + (str[sa[i]]!=str[sa[i-1]]);
    for (int k=1;k<=n;k<<=1){
        for (int j=0;j<n;j++){
            a[j]=rnk[j]+1;
            b[j]=(j+k>=n?0:rnk[j+k]+1);
            sa[j]=j;
        }
        radix(b,sa,rnk,n,n);
        radix(a,rnk,sa,n,n);
        rnk[sa[0]]=0;
        for (int i=1;i<n;i++)
            rnk[sa[i]] = rnk[sa[i-1]] + (a[sa[i]]!=a[sa[i-1]] || b[sa[i]]!=b[sa[i-1]]);
    }
}
int height[Maxn+5],rnk[Maxn+5];
inline void getHeight(int str[],int sa[],int rnk[],int height[],int n){
    for (int i=0;i<n;i++) rnk[sa[i]]=i;
    int k=0;
    height[0]=0;
    for (int i=0;i<n;i++){
        k=(k==0?0:k-1);
        if (rnk[i]!=0)
            while(str[i+k]==str[sa[rnk[i]-1]+k]) k++;
        height[rnk[i]]=k;
    }
}
char x[10];
char str[Maxn+5];
int istr[Maxn+5];
int len;
int nxt[Maxn+5];
inline void solve(int T){
    scanf("%s%s",x,str);
    len=strlen(str);
    //cout<<str<<endl;
    for (int i=0;i<len;i++) istr[i]=str[i]-'a'+1;
    SA(istr,sa,len,26);
    getHeight(istr,sa,rnk,height,len);
    int pre=len;
    for (int i=len;i>=0;i--){
        if (str[i]==x[0]) pre=i;
        nxt[i]=pre;
    }
    long long Ans=0;
    for (int i=0;i<len;i++)
        Ans += len - max(nxt[sa[i]],sa[i]+height[i]);
    /*for (int i=0;i<len;i++) printf("%d ",sa[i]);
    printf("\n");
    for (int i=0;i<len;i++) printf("%d ",height[i]);
    printf("\n");
    for (int i=1;i<=len;i++) printf("%d ",nxt[i]);
    printf("\n");
    */
    printf("Case #%d: %I64d\n",T,Ans);
}
int main(){
    //freopen("in.txt","r",stdin);
    int T;
    scanf("%d",&T);
    for (int i=1;i<=T;i++) solve(i);
    return 0;
}

Author : WNJXYK

Problem : HDU 5769

Blog : http://wnjxyk.cn

Date : 2016.7.30

#include<cstdio>

#include<cstdlib>

#include<ctime>

#include<iostream>

#include<algorithm>

#include<cstring>

#include<cmath>

#include<set>

#include<vector>

#include<map>

using namespace std;

const int Maxn=100000;

inline void radix(int str[],int pos[],int sa[],int n,int m){

static int cnt[Maxn+5];

memset(cnt,0,sizeof(cnt));

for (int i=0;i<n;i++) cnt[str[pos[i]]]++;

for (int i=1;i<=m;i++) cnt[i]+=cnt[i-1];

for (int i=n-1;i>=0;i--) sa[--cnt[str[pos[i]]]]=pos[i];

}

int sa[Maxn+5];

inline void SA(int str[],int sa[],int n,int m){

static int rnk[Maxn+5],a[Maxn+5],b[Maxn+5];

for (int i=0;i<n;i++) rnk[i]=i;

radix(str,rnk,sa,n,m);

rnk[sa[0]]=0;

for (int i=1;i<n;i++)

rnk[sa[i]] = rnk[sa[i-1]] + (str[sa[i]]!=str[sa[i-1]]);

for (int k=1;k<=n;k<<=1){

for (int j=0;j<n;j++){

a[j]=rnk[j]+1;

b[j]=(j+k>=n?0:rnk[j+k]+1);

sa[j]=j;

}

radix(b,sa,rnk,n,n);

radix(a,rnk,sa,n,n);

rnk[sa[0]]=0;

for (int i=1;i<n;i++)

rnk[sa[i]] = rnk[sa[i-1]] + (a[sa[i]]!=a[sa[i-1]] || b[sa[i]]!=b[sa[i-1]]);

}

int height[Maxn+5],rnk[Maxn+5];

inline void getHeight(int str[],int sa[],int rnk[],int height[],int n){

for (int i=0;i<n;i++) rnk[sa[i]]=i;

int k=0;

height[0]=0;

for (int i=0;i<n;i++){

k=(k==0?0:k-1);

if (rnk[i]!=0)

while(str[i+k]==str[sa[rnk[i]-1]+k]) k++;

height[rnk[i]]=k;

}

char x[10];

char str[Maxn+5];

int istr[Maxn+5];

int len;

int nxt[Maxn+5];

inline void solve(int T){

scanf("%s%s",x,str);

len=strlen(str);

//cout<<str<<endl;

for (int i=0;i<len;i++) istr[i]=str[i]-'a'+1;

SA(istr,sa,len,26);

getHeight(istr,sa,rnk,height,len);

int pre=len;

for (int i=len;i>=0;i--){

if (str[i]==x[0]) pre=i;

nxt[i]=pre;

}

long long Ans=0;

for (int i=0;i<len;i++)

Ans += len - max(nxt[sa[i]],sa[i]+height[i]);

/*for (int i=0;i<len;i++) printf("%d ",sa[i]);

printf("\n");

for (int i=0;i<len;i++) printf("%d ",height[i]);

printf("\n");

for (int i=1;i<=len;i++) printf("%d ",nxt[i]);

printf("\n");

printf("Case #%d: %I64d\n",T,Ans);

}

int main(){

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

int T;

scanf("%d",&T);

for (int i=1;i<=T;i++) solve(i);

return 0;

}

后缀数组

一	二	三	四	五	六	日
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23	24	25	26	27	28	29
30	31

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