字尾陣列模板

本模板最大亮點：自定義next函式

namespace SA{
    #define _next(_x) (_x+1)
    #define _check (y[sa[i]]!=y[sa[i-1]] || y[nxt[sa[i]]]!=y[nxt[sa[i-1]]])
    int nxt[MAXN], _nxt[MAXN];
    int x[MAXN], y[MAXN], c[MAXN], t[MAXN];
    int ranks[MAXN], sa[MAXN];
    int height[MAXN];
    int n, m;
    bool flag;
    char *s;
    inline int gainNext(int x){
        if(!x) return 0;
        return _next(x)>n?0:_next(x);
    }
    void init(char *_s, int _n, int _m){
        s = _s;
        n = _n;
        m = _m;
        flag = true;
    }
    void calc_height(){
        for(int i = 1; i <= n; i++) ranks[sa[i]] = i;
        for(int i = 1; i <= n; i++){
            if(ranks[i]==1) continue;
            int len = max(0, height[ranks[i-1]]-1);
            int j = sa[ranks[i]-1];
            while(i+len-1<n&&j+len-1<n&&s[i+len-1]==s[j+len-1]) len++;
            height[ranks[i]] = len;
        }
    }
    void solve(char *_s, int _n, int _m = 128){
        init(_s, _n, _m);
        for(int i = 1; i <= n; i++) nxt[i] = gainNext(i);
        for(int i = 1; i <= n; i++) x[i] = s[i];
        for(int i = 1; i <= n; i++) y[i] = i;
        //first sort
        for(int i = 0; i <= m; i++) c[i] = 0;
        for(int i = 1; i <= n; i++) c[x[i]]++;
        for(int i = 1; i <= m; i++) c[i] += c[i-1];
        for(int i = n; i >= 1; i--) sa[c[x[y[i]]]--] = y[i];
        for(int k = 1; k <= n && flag; k<<=1){
            // keywords2(seg2)
            for(int i = 1; i <= n; i++) ranks[sa[i]] = i;
            for(int i = 1; i <= n; i++) t[i] = ranks[nxt[i]];
            for(int i = 0; i <= n; i++) c[i] = 0;
            for(int i = 1; i <= n; i++) c[t[i]]++;
            for(int i = 1; i <= n; i++) c[i] += c[i-1];
            for(int i = n; i >= 1; i--) sa[c[t[i]]--] = i;
            for(int i = 1; i <= n; i++) y[i] = sa[i];
            // (log(k)+2)th sort
            for(int i = 0; i <= m; i++) c[i] = 0;
            for(int i = 1; i <= n; i++) c[x[i]]++;
            for(int i = 1; i <= m; i++) c[i] += c[i-1];
            for(int i = n; i >= 1; i--) sa[c[x[y[i]]]--] = y[i];
            int cnt = 0;    swap(x, y); // y->x throw,x->y save
            for(int i = 1; i <= n; i++) x[sa[i]] = _check?++cnt:cnt;
            cnt>=n?flag=false:m=cnt;
            swap(nxt, _nxt);
            for(int i = 1; i <= n; i++) nxt[i] = _nxt[_nxt[i]];
        }
        // Output();
        for(int i = 1; i <= n; i++) ranks[sa[i]] = i;
    }
    void Output(){
        static int len = 1;
        printf("========== len: %d ==========\n", len);
        for (int i = 1; i <= n; i++)
        {
            int now = sa[i];
            for (int j = 1; j <= n; j++)
            {
                printf("%c", now ? s[now - 1] : ' ');
                // printf("%d ", now);
                now = gainNext(now);
            }
            printf("\n");
        }
        printf("=============================\n", len);
        len *= 2;
    }
    void Output_(){
        static int len = 1;
        printf("========== len: %d ==========\n", len);
        for (int i = 1; i <= n; i++)
        {
            printf("%d%c", nxt[i], i == n ? '\n' : ' ');
        }
        printf("=============================\n", len);
        len *= 2;
    }
}

本作品採用《CC 協議》，轉載必須註明作者和本文連結