Super Functional Strings
Problem Statement :
We define a function, F, on a string, P , as follows: where: length(P) denotes the number of characters in string P. distinct(P) denotes the number of distinct characters in string P. Consuela loves creating string challenges and she needs your help testing her newest one! Given a string, S, consisting of N lowercase letters, compute the summation of function F (provided above) over all possible distinct substrings of S. As the result is quite large, print it modulo 10^9 + 7. Input Format The first line contains a single integer, T, denoting the number of test cases. Each of the T subsequent lines contains a string, S. Constraints 1 <= T <= 100 1 <= N <= 10^5 The sum of N over all test cases does not exceed . Output Format For each test case, print the answer modulo 10^9 + 7.
Solution :
Solution in C :
In C++ :
#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <vector>
#include <cstring>
#include <string>
#include <cmath>
#include <ctime>
#include <utility>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <sstream>
#define FOR(a,b,c) for (int a=b,_c=c;a<=_c;a++)
#define FORD(a,b,c) for (int a=b;a>=c;a--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; ++i)
#define REPD(i,a) for(int i=(a)-1; i>=0; --i)
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define sz(a) int(a.size())
#define reset(a,b) memset(a,b,sizeof(a))
#define oo 1000000007
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int maxn=200007;
int c[maxn],SA[maxn],RA[maxn],tSA[maxn],tRA[maxn],len;
int PLCP[maxn],LCP[maxn],pre[maxn];
char T[maxn];
int fRA(int v){return(v<=len?RA[v]:0);}
void sort(int k){
int t,sum,i,maxi=max(300,len);
FOR(i,0,maxi) c[i]=0;
FOR(i,1,len) {c[fRA(SA[i]+k)]++;}
for(i=sum=0; i<=maxi; i++){
t=c[i];
c[i]=sum;
sum+=t;
}
FOR(i,1,len) tSA[++c[fRA(SA[i]+k)]]=SA[i];
FOR(i,1,len) SA[i]=tSA[i];
}
void constructSA(){
int r;
FOR(i,1,len) RA[i]=T[i], SA[i]=i;
for(int k=1; k<len; k<<=1){
sort(k); sort(0);
r=tRA[SA[1]]=1;
FOR(i,2,len)
tRA[SA[i]]=(RA[SA[i]]==RA[SA[i-1]] && fRA(SA[i]+k)==fRA(SA[i-1]+k))?r:++r;
FOR(i,1,len) RA[i]=tRA[i];
}
int l=0;
pre[SA[1]]=-1;
FOR(i,2,len) pre[SA[i]]=SA[i-1];
FOR(i,1,len){
if(pre[i]==-1){PLCP[i]=0; continue;}
while(i+l<=len && pre[i]+l<=len && T[i+l]==T[pre[i]+l]) l++;
PLCP[i]=l;
l=max(l-1,0);
}
FOR(i,1,len) LCP[i]=PLCP[SA[i]];
}
int lastPos[26];
vector<int> jmp[maxn];
void constructJump(){
for(int i=0; i<26; ++i) lastPos[i]=len+1;
for(int i=len; i>=1; --i){
lastPos[T[i]-'a'] = i;
jmp[i].clear();
for(int v=0; v<26; ++v) if(lastPos[v]<=len) jmp[i].pb(lastPos[v]);
jmp[i].pb(len+1);
sort(jmp[i].begin(), jmp[i].end());
}
}
ll sum[27][maxn];
ll p[maxn];
void init(){
for(int i=1; i<=100000; ++i) p[i]=1;
for(int j=1; j<=26; ++j){
for(int i=1; i<=100000; ++i){
p[i] = p[i]*i%oo;
sum[j][i]=sum[j][i-1]+p[i];
}
}
}
ll cal(int start, int finish){
if(finish < start) return 0;
int u = start;
ll res = 0;
for(int i=1; i<sz(jmp[start]) && u<=finish; ++i){
int v = jmp[start][i];
if(v > finish+1) v = finish+1;
res = (res + (sum[i][v-start] - sum[i][u-start]) + oo)%oo;
u = v;
}
return res;
}
void solve(){
ll res = 0;
for(int i=1; i<=len; ++i){
int start=SA[i];
res = (res - cal(start, start + LCP[i] - 1) + oo)%oo;
res = (res + cal(start, len))%oo;
}
cout<<res<<endl;
}
int main(){
// freopen("input.txt","r",stdin);
int nTest;
scanf("%d",&nTest);
init();
while(nTest--){
scanf("%s",T+1); len=strlen(T+1);
constructSA();
constructJump();
solve();
}
}
In Java :
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
public class D {
InputStream is;
PrintWriter out;
String INPUT = "";
void solve()
{
int mod = 1000000007;
long[][] psums = new long[27][100005];
long[] tp = new long[100005];
Arrays.fill(tp, 1);
for(int i = 0;i < 27;i++){
psums[i][0] = 1;
for(int j = 1;j < 100005;j++){
psums[i][j] = psums[i][j-1] + tp[j];
if(psums[i][j] >= mod)psums[i][j] -= mod;
tp[j] = tp[j] * j % mod;
}
}
for(int T = ni();T > 0;T--){
char[] s = ns().toCharArray();
int n = s.length;
int[][] nexts = new int[n+1][26];
Arrays.fill(nexts[n], n);
// +1
for(int j = n-1;j >= 0;j--){
for(int k = 0;k < 26;k++){
nexts[j][k] = nexts[j+1][k];
}
nexts[j][s[j]-'a'] = j;
}
int[] sa = sa(s);
int[] lcp = buildLCP(s, sa);
long ret = 0;
for(int i = 0;i < n;i++){
// lcp+1,...,n-sa[i]
Arrays.sort(nexts[sa[i]]);
for(int j = 1;j <= 26;j++){
int ne = j == 26 ? n-sa[i] : nexts[sa[i]][j]-sa[i];
int pr = nexts[sa[i]][j-1]-sa[i]+1;
// [pr,ne)
// tr(j, pr, ne, lcp[i]+1);
pr = Math.max(pr, lcp[i]+1);
if(pr <= ne){
ret += psums[j][ne]-psums[j][pr-1];
}
}
}
ret %= mod;
if(ret < 0)ret += mod;
out.println(ret);
}
}
private static interface BaseArray {
public int get(int i);
public void set(int i, int val);
public int update(int i, int val);
}
private static class CharArray implements BaseArray {
private char[] m_A = null;
private int m_pos = 0;
CharArray(char[] A, int pos) {
m_A = A;
m_pos = pos;
}
public int get(int i) {
return m_A[m_pos + i] & 0xffff;
}
public void set(int i, int val) {
m_A[m_pos + i] = (char) (val & 0xffff);
}
public int update(int i, int val) {
return m_A[m_pos + i] += val & 0xffff;
}
}
private static class IntArray implements BaseArray {
private int[] m_A = null;
private int m_pos = 0;
IntArray(int[] A, int pos) {
m_A = A;
m_pos = pos;
}
public int get(int i) {
return m_A[m_pos + i];
}
public void set(int i, int val) {
m_A[m_pos + i] = val;
}
public int update(int i, int val) {
return m_A[m_pos + i] += val;
}
}
/* find the start or end of each bucket */
private static void getCounts(BaseArray T, BaseArray C, int n, int k) {
int i;
for(i = 0;i < k;++i){
C.set(i, 0);
}
for(i = 0;i < n;++i){
C.update(T.get(i), 1);
}
}
private static void getBuckets(BaseArray C, BaseArray B, int k, boolean end) {
int i, sum = 0;
if(end != false){
for(i = 0;i < k;++i){
sum += C.get(i);
B.set(i, sum);
}
}else{
for(i = 0;i < k;++i){
sum += C.get(i);
B.set(i, sum - C.get(i));
}
}
}
/* sort all type LMS suffixes */
private static void LMSsort(BaseArray T, int[] SA, BaseArray C,
BaseArray B, int n, int k) {
int b, i, j;
int c0, c1;
/* compute SAl */
if(C == B){
getCounts(T, C, n, k);
}
getBuckets(C, B, k, false); /* find starts of buckets */
j = n - 1;
b = B.get(c1 = T.get(j));
--j;
SA[b++] = (T.get(j) < c1) ? ~j : j;
for(i = 0;i < n;++i){
if(0 < (j = SA[i])){
if((c0 = T.get(j)) != c1){
B.set(c1, b);
b = B.get(c1 = c0);
}
--j;
SA[b++] = (T.get(j) < c1) ? ~j : j;
SA[i] = 0;
}else if(j < 0){
SA[i] = ~j;
}
}
/* compute SAs */
if(C == B){
getCounts(T, C, n, k);
}
getBuckets(C, B, k, true); /* find ends of buckets */
for(i = n - 1, b = B.get(c1 = 0);0 <= i;--i){
if(0 < (j = SA[i])){
if((c0 = T.get(j)) != c1){
B.set(c1, b);
b = B.get(c1 = c0);
}
--j;
SA[--b] = (T.get(j) > c1) ? ~(j + 1) : j;
SA[i] = 0;
}
}
}
private static int LMSpostproc(BaseArray T, int[] SA, int n, int m) {
int i, j, p, q, plen, qlen, name;
int c0, c1;
boolean diff;
/*
* compact all the sorted substrings into the first m items of SA 2*m
* must be not larger than n (proveable)
*/
for(i = 0;(p = SA[i]) < 0;++i){
SA[i] = ~p;
}
if(i < m){
for(j = i, ++i;;++i){
if((p = SA[i]) < 0){
SA[j++] = ~p;
SA[i] = 0;
if(j == m){
break;
}
}
}
}
/* store the length of all substrings */
i = n - 1;
j = n - 1;
c0 = T.get(n - 1);
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) >= c1));
for(;0 <= i;){
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) <= c1));
if(0 <= i){
SA[m + ((i + 1) >> 1)] = j - i;
j = i + 1;
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) >= c1));
}
}
/* find the lexicographic names of all substrings */
for(i = 0, name = 0, q = n, qlen = 0;i < m;++i){
p = SA[i];
plen = SA[m + (p >> 1)];
diff = true;
if((plen == qlen) && ((q + plen) < n)){
for(j = 0;(j < plen) && (T.get(p + j) == T.get(q + j));++j){
}
if(j == plen){
diff = false;
}
}
if(diff != false){
++name;
q = p;
qlen = plen;
}
SA[m + (p >> 1)] = name;
}
return name;
}
/* compute SA and BWT */
private static void induceSA(BaseArray T, int[] SA, BaseArray C,
BaseArray B, int n, int k) {
int b, i, j;
int c0, c1;
/* compute SAl */
if(C == B){
getCounts(T, C, n, k);
}
getBuckets(C, B, k, false); /* find starts of buckets */
j = n - 1;
b = B.get(c1 = T.get(j));
SA[b++] = ((0 < j) && (T.get(j - 1) < c1)) ? ~j : j;
for(i = 0;i < n;++i){
j = SA[i];
SA[i] = ~j;
if(0 < j){
if((c0 = T.get(--j)) != c1){
B.set(c1, b);
b = B.get(c1 = c0);
}
SA[b++] = ((0 < j) && (T.get(j - 1) < c1)) ? ~j : j;
}
}
/* compute SAs */
if(C == B){
getCounts(T, C, n, k);
}
getBuckets(C, B, k, true); /* find ends of buckets */
for(i = n - 1, b = B.get(c1 = 0);0 <= i;--i){
if(0 < (j = SA[i])){
if((c0 = T.get(--j)) != c1){
B.set(c1, b);
b = B.get(c1 = c0);
}
SA[--b] = ((j == 0) || (T.get(j - 1) > c1)) ? ~j : j;
}else{
SA[i] = ~j;
}
}
}
/*
* find the suffix array SA of T[0..n-1] in {0..k-1}^n use a working space
* (excluding T and SA) of at most 2n+O(1) for a constant alphabet
*/
private static void SA_IS(BaseArray T, int[] SA, int fs, int n, int k) {
BaseArray C, B, RA;
int i, j, b, m, p, q, name, newfs;
int c0, c1;
int flags = 0;
if(k <= 256){
C = new IntArray(new int[k], 0);
if(k <= fs){
B = new IntArray(SA, n + fs - k);
flags = 1;
}else{
B = new IntArray(new int[k], 0);
flags = 3;
}
}else if(k <= fs){
C = new IntArray(SA, n + fs - k);
if(k <= (fs - k)){
B = new IntArray(SA, n + fs - k * 2);
flags = 0;
}else if(k <= 1024){
B = new IntArray(new int[k], 0);
flags = 2;
}else{
B = C;
flags = 8;
}
}else{
C = B = new IntArray(new int[k], 0);
flags = 4 | 8;
}
/*
* stage 1: reduce the problem by at least 1/2 sort all the
* LMS-substrings
*/
getCounts(T, C, n, k);
getBuckets(C, B, k, true); /* find ends of buckets */
for(i = 0;i < n;++i){
SA[i] = 0;
}
b = -1;
i = n - 1;
j = n;
m = 0;
c0 = T.get(n - 1);
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) >= c1));
for(;0 <= i;){
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) <= c1));
if(0 <= i){
if(0 <= b){
SA[b] = j;
}
b = B.update(c1, -1);
j = i;
++m;
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) >= c1));
}
}
if(1 < m){
LMSsort(T, SA, C, B, n, k);
name = LMSpostproc(T, SA, n, m);
}else if(m == 1){
SA[b] = j + 1;
name = 1;
}else{
name = 0;
}
/*
* stage 2: solve the reduced problem recurse if names are not yet
* unique
*/
if(name < m){
if((flags & 4) != 0){
C = null;
B = null;
}
if((flags & 2) != 0){
B = null;
}
newfs = (n + fs) - (m * 2);
if((flags & (1 | 4 | 8)) == 0){
if((k + name) <= newfs){
newfs -= k;
}else{
flags |= 8;
}
}
for(i = m + (n >> 1) - 1, j = m * 2 + newfs - 1;m <= i;--i){
if(SA[i] != 0){
SA[j--] = SA[i] - 1;
}
}
RA = new IntArray(SA, m + newfs);
SA_IS(RA, SA, newfs, m, name);
RA = null;
i = n - 1;
j = m * 2 - 1;
c0 = T.get(n - 1);
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) >= c1));
for(;0 <= i;){
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) <= c1));
if(0 <= i){
SA[j--] = i + 1;
do{
c1 = c0;
}while ((0 <= --i) && ((c0 = T.get(i)) >= c1));
}
}
for(i = 0;i < m;++i){
SA[i] = SA[m + SA[i]];
}
if((flags & 4) != 0){
C = B = new IntArray(new int[k], 0);
}
if((flags & 2) != 0){
B = new IntArray(new int[k], 0);
}
}
/* stage 3: induce the result for the original problem */
if((flags & 8) != 0){
getCounts(T, C, n, k);
}
/* put all left-most S characters into their buckets */
if(1 < m){
getBuckets(C, B, k, true); /* find ends of buckets */
i = m - 1;
j = n;
p = SA[m - 1];
c1 = T.get(p);
do{
q = B.get(c0 = c1);
while (q < j){
SA[--j] = 0;
}
do{
SA[--j] = p;
if(--i < 0){
break;
}
p = SA[i];
}while ((c1 = T.get(p)) == c0);
}while (0 <= i);
while (0 < j){
SA[--j] = 0;
}
}
induceSA(T, SA, C, B, n, k);
C = null;
B = null;
}
/* char */
public static void suffixsort(char[] T, int[] SA, int n) {
if((T == null) || (SA == null) || (T.length < n) || (SA.length < n)){
return;
}
if(n <= 1){
if(n == 1){
SA[0] = 0;
}
return;
}
SA_IS(new CharArray(T, 0), SA, 0, n, 128);
}
public static int[] sa(char[] T)
{
int n = T.length;
int[] sa = new int[n];
suffixsort(T, sa, n);
return sa;
}
public static int[] buildLCP(char[] str, int[] sa)
{
int n = str.length;
int h = 0;
int[] lcp = new int[n];
int[] isa = new int[n];
for(int i = 0;i < n;i++)isa[sa[i]] = i;
for(int i = 0;i < n;i++){
if(isa[i] > 0){
for(int j = sa[isa[i]-1]; j+h<n && i+h<n && str[j+h] == str[i+h]; h++);
lcp[isa[i]] = h;
}else{
lcp[isa[i]] = 0;
}
if(h > 0)h--;
}
return lcp;
}
void run() throws Exception
{
is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
out = new PrintWriter(System.out);
long s = System.currentTimeMillis();
solve();
out.flush();
if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
}
public static void main(String[] args) throws Exception { new D().run(); }
private byte[] inbuf = new byte[1024];
private int lenbuf = 0, ptrbuf = 0;
private int readByte()
{
if(lenbuf == -1)throw new InputMismatchException();
if(ptrbuf >= lenbuf){
ptrbuf = 0;
try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
if(lenbuf <= 0)return -1;
}
return inbuf[ptrbuf++];
}
private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
private double nd() { return Double.parseDouble(ns()); }
private char nc() { return (char)skip(); }
private String ns()
{
int b = skip();
StringBuilder sb = new StringBuilder();
while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
private char[] ns(int n)
{
char[] buf = new char[n];
int b = skip(), p = 0;
while(p < n && !(isSpaceChar(b))){
buf[p++] = (char)b;
b = readByte();
}
return n == p ? buf : Arrays.copyOf(buf, p);
}
private char[][] nm(int n, int m)
{
char[][] map = new char[n][];
for(int i = 0;i < n;i++)map[i] = ns(m);
return map;
}
private int[] na(int n)
{
int[] a = new int[n];
for(int i = 0;i < n;i++)a[i] = ni();
return a;
}
private int ni()
{
int num = 0, b;
boolean minus = false;
while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
if(b == '-'){
minus = true;
b = readByte();
}
while(true){
if(b >= '0' && b <= '9'){
num = num * 10 + (b - '0');
}else{
return minus ? -num : num;
}
b = readByte();
}
}
private long nl()
{
long num = 0;
int b;
boolean minus = false;
while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
if(b == '-'){
minus = true;
b = readByte();
}
while(true){
if(b >= '0' && b <= '9'){
num = num * 10 + (b - '0');
}else{
return minus ? -num : num;
}
b = readByte();
}
}
private static void tr(Object... o)
{ System.out.println(Arrays.deepToString(o)); }
}
In C :
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define A_SIZE 26
#define MIN_C 'a'
#define MOD 1000000007
typedef struct _st_node st_node;
typedef struct _st_edge st_edge;
struct _st_node{
st_node *suffix_link;
st_edge *edges[A_SIZE+1];
};
struct _st_edge{
int from;
int to;
int suffix_index;
st_node *node;
};
void print(st_node *root,int len);
void suffix_tree(st_node *root,char *str,int len);
long long modPow(long long a,int x);
void sort_a(int*a,int size);
void merge(int*a,int*left,int*right,int left_size, int right_size);
char str[100001];
int dp[100000][26];
long long ans,pows[26][100001];
int main(){
int T,len,i,j;
st_node root;
for(i=0;i<26;i++)
for(j=1;j<=100000;j++)
pows[i][j]=(pows[i][j-1]+modPow(j,i+1))%MOD;
scanf("%d",&T);
while(T--){
scanf("%s",str);
len=strlen(str);
for(i=0;i<26;i++)
dp[len-1][i]=-1;
dp[len-1][str[len-1]-MIN_C]=len-1;
for(i=len-2;i>=0;i--){
memcpy(&dp[i][0],&dp[i+1][0],26*sizeof(int));
dp[i][str[i]-MIN_C]=i;
}
suffix_tree(&root,str,len);
ans=0;
print(&root,0);
printf("%lld\n",ans);
}
return 0;
}
void print(st_node *root,int len){
int i,j,idx,from,to,s,dc,last,t,a[26];
if(!root)
return;
for(i=0;i<A_SIZE;i++)
if(root->edges[i]){
idx=root->edges[i]->suffix_index;
from=idx+len;
to=idx+len+root->edges[i]->to-root->edges[i]->from;
s=dc=0;
last=idx+len-1;
for(j=0;j<26;j++)
if(dp[idx][j]!=-1 && dp[idx][j]<from)
dc++;
else if(dp[idx][j]>=from && dp[idx][j]<=to)
a[s++]=dp[idx][j];
sort_a(a,s);
for(j=0;j<s;j++,dc++){
t=a[j]-1;
if(dc)
ans=(ans+pows[dc-1][t-idx+1]-pows[dc-1][last-idx+1]+MOD)%MOD;
last=t;
}
t=to;
ans=(ans+pows[dc-1][t-idx+1]-pows[dc-1][last-idx+1]+MOD)%MOD;
print(root->edges[i]->node,len+root->edges[i]->to-root->edges[i]->from+1);
}
return;
}
void suffix_tree(st_node *root,char *str,int len){
int a_edge,a_len=0,remainder=0,need_insert,from,i;
st_node *a_node=root,*pre_node,*t_node;
st_edge *t_edge;
memset(root,0,sizeof(st_node));
for(i=0;i<=len;i++){
need_insert=0;
pre_node=NULL;
remainder++;
if(i==len)
need_insert=1;
else if(a_len)
if(str[a_node->edges[a_edge]->from+a_len]==str[i])
if(a_node->edges[a_edge]->from+a_len==a_node->edges[a_edge]->to){
a_node=a_node->edges[a_edge]->node;
a_len=0;
}
else
a_len++;
else
need_insert=1;
else
if(a_node->edges[str[i]-MIN_C])
if(a_node->edges[str[i]-MIN_C]->from==a_node->edges[str[i]-MIN_C]->to)
a_node=a_node->edges[str[i]-MIN_C]->node;
else{
a_edge=str[i]-MIN_C;
a_len=1;
}
else
need_insert=1;
if(need_insert)
for(;remainder>0;remainder--){
if(!a_len)
if(i==len){
a_node->edges[A_SIZE]=(st_edge*)malloc(sizeof(st_edge));
a_node->edges[A_SIZE]->suffix_index=i-remainder+1;
a_node->edges[A_SIZE]->node=NULL;
}
else{
if(a_node->edges[str[i]-MIN_C]){
if(pre_node)
pre_node->suffix_link=a_node;
if(a_node->edges[str[i]-MIN_C]->from==a_node->edges[str[i]-MIN_C]->to)
a_node=a_node->edges[str[i]-MIN_C]->node;
else{
a_edge=str[i]-MIN_C;
a_len=1;
}
break;
}
t_edge=(st_edge*)malloc(sizeof(st_edge));
t_edge->from=i;
t_edge->to=len-1;
t_edge->suffix_index=i-remainder+1;
t_edge->node=NULL;
a_node->edges[str[i]-MIN_C]=t_edge;
t_node=a_node;
}
else{
if(i!=len && str[a_node->edges[a_edge]->from+a_len]==str[i]){
if(pre_node)
pre_node->suffix_link=a_node;
if(a_node->edges[a_edge]->from+a_len==a_node->edges[a_edge]->to){
a_node=a_node->edges[a_edge]->node;
a_len=0;
}
else
a_len++;
break;
}
t_node=(st_node*)malloc(sizeof(st_node));
memset(t_node,0,sizeof(st_node));
t_edge=(st_edge*)malloc(sizeof(st_edge));
t_edge->from=a_node->edges[a_edge]->from+a_len;
t_edge->to=a_node->edges[a_edge]->to;
t_edge->suffix_index=a_node->edges[a_edge]->suffix_index;
t_edge->node=a_node->edges[a_edge]->node;
from=a_node->edges[a_edge]->from;
a_node->edges[a_edge]->node=t_node;
a_node->edges[a_edge]->to=a_node->edges[a_edge]->from+a_len-1;
t_node->edges[str[t_edge->from]-MIN_C]=t_edge;
if(i==len){
t_node->edges[A_SIZE]=(st_edge*)malloc(sizeof(st_edge));
t_node->edges[A_SIZE]->suffix_index=i-remainder+1;
t_node->edges[A_SIZE]->node=NULL;
}
else{
t_edge=(st_edge*)malloc(sizeof(st_edge));
t_edge->from=i;
t_edge->to=len-1;
t_edge->suffix_index=i-remainder+1;
t_edge->node=NULL;
t_node->edges[str[i]-MIN_C]=t_edge;
}
}
if(pre_node)
pre_node->suffix_link=t_node;
pre_node=t_node;
if(a_node==root && a_len>0){
if(remainder>1)
a_edge=str[i-remainder+2]-MIN_C;
from=i-remainder+2;
a_len--;
}
else if(a_node!=root)
if(a_node->suffix_link)
a_node=a_node->suffix_link;
else
a_node=root;
while(a_len>0 && a_len>=a_node->edges[a_edge]->to-a_node->edges[a_edge]->from+1){
a_len-=a_node->edges[a_edge]->to-a_node->edges[a_edge]->from+1;
from+=a_node->edges[a_edge]->to-a_node->edges[a_edge]->from+1;
a_node=a_node->edges[a_edge]->node;
a_edge=str[from]-MIN_C;
}
}
}
return;
}
long long modPow(long long a,int x){
long long res = 1;
while(x>0){
if(x%2)
res=(res*a)%MOD;
a=(a*a)%MOD;
x>>=1;
}
return res;
}
void sort_a(int*a,int size){
if (size < 2)
return;
int m = (size+1)/2,i;
int *left,*right;
left=(int*)malloc(m*sizeof(int));
right=(int*)malloc((size-m)*sizeof(int));
for(i=0;i<m;i++)
left[i]=a[i];
for(i=0;i<size-m;i++)
right[i]=a[i+m];
sort_a(left,m);
sort_a(right,size-m);
merge(a,left,right,m,size-m);
free(left);
free(right);
return;
}
void merge(int*a,int*left,int*right,int left_size, int right_size){
int i = 0, j = 0;
while (i < left_size|| j < right_size) {
if (i == left_size) {
a[i+j] = right[j];
j++;
} else if (j == right_size) {
a[i+j] = left[i];
i++;
} else if (left[i] <= right[j]) {
a[i+j] = left[i];
i++;
} else {
a[i+j] = right[j];
j++;
}
}
return;
}
In Python3 :
from string import ascii_lowercase
from bisect import bisect_left, bisect_right
from itertools import zip_longest, islice
MOD = 7 + 10 ** 9
N = 10 ** 5
sum_pow = [[0] * (N + 1) for k in range(27)]
for k in range(1, 27):
for n in range(1, N + 1):
sum_pow[k][n] = (sum_pow[k][n - 1] + pow(n, k, MOD)) % MOD
def get_sp(left, right, k):
if left > right or right <= 0:
return 0
if left <= 0:
return sum_pow[k][right]
return (sum_pow[k][right] + MOD - sum_pow[k][left - 1]) % MOD
def all_occ(s):
n = len(s)
occ = [[] for _ in range(26)]
for i in range(n):
occ[ord(s[i]) - ord('a')].append(i)
return occ
def occ_from_i(occ, i):
occ_i = []
for j in range(26):
if len(occ[j]) == 0 or i > occ[j][-1]:
continue
first = bisect_left(occ[j], i)
occ_i.append(occ[j][first])
return sorted(occ_i)
def sorted_idx(items):
unique = sorted(set(items))
idx = dict(zip(unique, range(len(unique))))
return [idx[v] for v in items]
def suffix_array(s):
n = len(s)
k = 1
sa = sorted_idx(s)
while max(sa) < n - 1:
sa = sorted_idx([a * (n + 1) + b + 1 for
(a, b) in zip_longest(sa,
islice(sa, k, None),
fillvalue=-1)])
k <<= 1
return sa
def lcp_sa(s):
inv_sa = suffix_array(s)
n = len(inv_sa)
sa = [0] * n
for i in range(n):
sa[inv_sa[i]] = i
lcp = [0] * n
k = 0
for i in range(n):
if inv_sa[i] == n - 1:
k = 0
continue
j = sa[inv_sa[i]+1]
while i + k < n and j + k < n and s[i + k] == s[j + k]:
k += 1
lcp[inv_sa[i] + 1] = k
if k > 0:
k -= 1
return sa, lcp
def solve(s):
n = len(s)
occ = all_occ(s)
sa, lcp = lcp_sa(s)
ans = 0
#print(sa)
#print(lcp)
for i in range(n):
o = occ_from_i(occ, sa[i])
t = sa[i] + lcp[i]
if t >= o[-1]:
ans = (ans + get_sp(lcp[i] + 1, n - sa[i], len(o))) % MOD
continue
k = bisect_right(o, t)
ans = (ans + get_sp(lcp[i] + 1, o[k] - sa[i], k)) % MOD
for j in range(k + 1, len(o)):
ans = (ans + get_sp(o[j - 1] - sa[i] + 1, o[j] - sa[i], j)) % MOD
ans = (ans + get_sp(o[-1] - sa[i] + 1, n - sa[i], len(o))) % MOD
return ans
def sum_p_bf(left, right, k):
ans = 0
for n in range(max(left, 1), right + 1):
ans = (ans + pow(n, k, MOD)) % MOD
return ans
q = int(input().strip())
for _ in range(q):
string = input().strip()
print(solve(string))
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