CSU-1632 Repeated Substrings （后缀数组）

//# define AC

# ifndef AC

# include<iostream>
# include<cstdio>
# include<cstring>
# include<vector>
# include<queue>
# include<list>
# include<cmath>
# include<set>
# include<map>
# include<string>
# include<cstdlib>
# include<algorithm>
using namespace std;
# define mid (l+(r-l)/2)

typedef long long LL;
typedef unsigned long long ULL;

const int N=100000;
const int mod=1e9+7;
const int INF=0x7fffffff;
const LL oo=0x7fffffffffffffff;

int SA[N+5];
int tSA[N+5];
int cnt[N+5];
int rk[N+5];
int *x,*y;
int height[N+5];

int idx(char c)
{
    if(‘a‘<=c&&c<=‘z‘) return c-‘a‘;
    return c-‘A‘+26;
}

bool same(int i,int j,int k,int n)
{
    if(y[i]-y[j]) return false;
    if(i+k<n&&j+k>=n) return false;
    if(i+k>=n&&j+k<n) return false;
    return y[i+k]==y[j+k];
}

void buildSA(char *s)
{
    int n=strlen(s);
    int m=52;
    x=rk,y=tSA;
    for(int i=0;i<m;++i) cnt[i]=0;
    for(int i=0;i<n;++i) ++cnt[x[i]=idx(s[i])];
    for(int i=1;i<m;++i) cnt[i]+=cnt[i-1];
    for(int i=n-1;i>=0;--i) SA[--cnt[x[i]]]=i;

    for(int k=1;k<=n;k<<=1){
        int p=0;
        for(int i=n-k;i<n;++i) y[p++]=i;
        for(int i=0;i<n;++i) if(SA[i]>=k) y[p++]=SA[i]-k;

        for(int i=0;i<m;++i) cnt[i]=0;
        for(int i=0;i<n;++i) ++cnt[x[y[i]]];
        for(int i=1;i<m;++i) cnt[i]+=cnt[i-1];
        for(int i=n-1;i>=0;--i) SA[--cnt[x[y[i]]]]=y[i];

        p=1;
        swap(x,y);
        x[SA[0]]=0;
        for(int i=1;i<n;++i)
            x[SA[i]]=same(SA[i],SA[i-1],k,n)?p-1:p++;
        if(p>=n) break;
        m=p;
    }
}

void getHeight(char *s)
{
    int n=strlen(s);
    for(int i=0;i<n;++i) rk[SA[i]]=i;
    int k=0;
    for(int i=0;i<n;++i){
        if(rk[i]==0){
            height[rk[i]]=k=0;
        }else{
            if(k) --k;
            int j=SA[rk[i]-1];
            while(i+k<n&&j+k<n&&s[i+k]==s[j+k])
                ++k;
            height[rk[i]]=k;
        }
    }
}

char str[N+5];

void solve()
{
    int n=strlen(str);
    int ans=0;
    for(int i=0;i<n;++i){
        if(height[i]>height[i-1])
            ans+=height[i]-height[i-1];
    }
    printf("%d\n",ans);
}

int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%s",str);
        buildSA(str);
        getHeight(str);
        solve();
    }
    return 0;
}

# endif