后缀数组模板/LCP模板

 //后缀数组模板，MANX为数组的大小
 //支持的操作有计算后缀数组(sa数组)， 计算相邻两元素的最长公共前缀(height数组)，使用get_height();
 //计算两个后缀a, 和b的最长公共前缀，请先使用lcp_init(),再调用get_lcp(a, b)得到
 //下面的n是输入字符串的长度+1(n = strlen(s) + 1)， m是模板的范围 m=128表示在字母，数字范围内，可以扩大也可缩小
 //s[len] 是插入的一个比输入字符都要小的字符
 struct SufArray {
     char s[MAXN];
     int sa[MAXN], t[MAXN], t2[MAXN], c[MAXN], n, m;
     int rnk[MAXN], height[MAXN];//rnk和height数组
     int mi[MAXN][], idxK[MAXN];//用于计算LCP

     void init() {
         mem0(s);
         mem0(height);
     }
     //读入字符串作为输入
     void read_str() {
         gets(s);
         m = ;
         n = strlen(s);
         s[n++] = ' ';
     }
     void build_sa() {
         int *x = t, *y = t2;
         rep (i, , m - ) c[i] = ;
         rep (i, , n - ) c[x[i] = s[i]] ++;
         rep (i, , m - ) c[i] += c[i - ];
         dec (i, n - , ) sa[--c[x[i]]] = i;
         for(int k = ; k <= n; k <<= ) {
             int p = ;
             rep (i, n - k, n - ) y[p++] = i;
             rep (i, , n - ) if(sa[i] >= k) y[p++] = sa[i] - k;
             rep (i, , m - ) c[i] = ;
             rep (i, , n - ) c[x[y[i]]] ++;
             rep (i, , m - ) c[i] += c[i - ];
             dec (i, n - , ) sa[--c[x[y[i]]]] = y[i];
             swap(x, y);
             p = ;
             x[sa[]] = ;
             rep (i, , n - ) {
                 x[sa[i]] = y[sa[i - ]] == y[sa[i]] && y[sa[i - ] + k] == y[sa[i] + k] ? p -  : p++;
             }
             if(p >= n) break;
             m = p;
         }
     }
     void get_height() {
         int k = ;
         rep (i, , n - ) rnk[sa[i]] = i;
         rep (i, , n - ) {
             if(k) k --;
             int j = sa[rnk[i] - ];
             while(s[i + k] == s[j + k]) k ++;
             height[rnk[i]] = k;
         }
     }
     void rmq_init(int *a, int n) {
         rep (i, , n - ) mi[i][] = a[i];
         for(int j = ; ( << j) <= n; j ++) {
             for(int i = ; i + (<<j) -  < n; i ++) {
                 mi[i][j] = min(mi[i][j - ], mi[i + ( << (j - ))][j - ]);
             }
         }
         rep (len, , n) {
             idxK[len] = ;
             while(( << (idxK[len] + )) <= len) idxK[len] ++;
         }
     }
     int rmq_min(int l, int r) {
         int len = r - l + , k = idxK[len];
         return min(mi[l][k], mi[r - ( << k) + ][k]);
     }
     void lcp_init() {
         get_height();
         rmq_init(height, n);
     }
     int get_lcp(int a, int b) {
         if(a == b) return n - a - ;
         return rmq_min(min(rnk[a], rnk[b]) + , max(rnk[a], rnk[b]));
     }
     void solve() {
     }
 };