CF (427d-match & Catch) suffix Array application

Test instructions: For two strings, find the shortest substring. The number of occurrences of this substring in two strings equals 1. The occurrence is defined as: capable of overlapping occurrences.

Solution: The application of the suffix array. Small enumeration length. Suppose a length len is valid: Then there must be this kind of sa[i] rank. The public prefix length of sa[i] and s[i+1] is greater than or equal to Len, and the public prefix length of sa[i] and [i-1] is less than Len, the same time sa[i+1] and [i+2] The public prefix length is less than Len, at the same time guaranteed sa[i] and sa[i+1] in two strings. The judge function is the skillful implementation of these inferences.

Code:

#include <iostream> #include <string> #include <cstring> #include <string.h> #include < stdio.h>using namespace Std;const int MAX = 200100;int N, num[max];int Sa[max], Rank[max], Height[max];//sa[i] Height[i] (suffix sa[i] and sa[i-1] the longest common prefix int wa[max], Wb[max], Wv[max], wd[max];//name Group Rank[i] Save Suffix (i) Rank from small to large in all suffixes. To put it simply, the suffix Array (SA) is "Who is the first row?" The rank Array (rank) is "What's your rank?" ” 。 Easy to see, the suffix array and the rank array are mutually inverse. int cmp (int *r, int A, int b, int l) {return r[a] = = R[b] && r[a+l] = = R[b+l];} void da (int *r, int n, int m)//multiplication algorithm 0 (NLGN).    {int I, J, p, *x = WA, *y = WB, *t;    for (i = 0; i < m; i + +) wd[i] = 0;    for (i = 0; i < n; i + +) Wd[x[i]=r[i]] + +;    for (i = 1; i < m; i + +) Wd[i] + = wd[i-1];    for (i = n-1; I >= 0; i-) sa[--wd[x[i]] [= i;        for (j = 1, p = 1; p < n; j *= 2, M = p) {for (P = 0, i = n-j; i < n; i + +) Y[p + +] = i;        for (i = 0; i < n; i + +) if (Sa[i] >= j) Y[p + +] = sa[i]-J; For (i = 0; i < n; i + +) wv[i] = x[y[i]];        for (i = 0; i < m; i + +) wd[i] = 0;        for (i = 0; i < n; i + +) Wd[wv[i]] + +;        for (i = 1; i < m; i + +) Wd[i] + = wd[i-1];        for (i = n-1; I >= 0; i-) sa[--wd[wv[i]] [= Y[i];  for (t = x, x = y, y = t, p = 1, x[sa[0]] = 0, i = 1; i < n; i + +) {X[sa[i]] = cmp (y, sa[i-1], Sa[i], j)?        P-1: P + +; }}}void calheight (int *r, int n)//height array.    {int I, j, k = 0;    for (i = 0; i < n; i + +) rank[sa[i]] = i;    for (i = 0; i < n; height[rank[i + +]] = k) {for (k K--: 0, j = sa[rank[i]-1]; r[i+k] = = R[j+k]; k + +);    }}int len1=0;int Len2=0;char s1[10000];char s2[10000];bool Judge (int n,int k) {int a = 0,b = 0;             for (int i = 0;i < n;i++) {if (Height[i] < K) {if (a = = 1 && b = = 1) return 1;        A = b = 0;        } if (Sa[i] >= 0 && sa[i] < len1) a++; if (Sa[i] > Len1 && Sa[i] < n-1) b++; } return 0;}    int main () {scanf ("%s%s", S1,S2);    Len1=strlen (S1);    Len2=strlen (S2);    for (int i=0; i<len1; i++) num[i]=s1[i]-' a ' +1;    num[len1]=28;    for (int i=0; i<len2; i++) num[i+len1+1]=s2[i]-' a ' +1;    Da (num,len1+len2+2,30);    Calheight (num,len1+len2+2);    int len=min (LEN1,LEN2);    int ans=-1;            for (int i=1; i<=len; i++) {if (Judge (len1+len2+2,i)) {ans=i;        Break    }} cout<<ans<<endl; return 0;} 20 5 19 20 19 5 20 19 5 19 28 20 5 5 16 20 5 19 0 0 0

CF (427d-match & Catch) suffix Array application