Good Article Good sentence HDOJ4416

做了这题，不得不说对后缀数组的理解还是不深刻（感觉这题SAM也可以搞，等学透了SAM再来看看这题），题意就是求第一个串S1中有多少个子串不是其他串Si(i > 1)的子串，老规矩，先把串都连接起来，中间用不同的字符连接起来， 然后求每个S1的后缀与其他串Si的后缀的lcp，这表明该后缀有lcp的子串是其他串的子串，这里求lcp不用把每个S1的后缀与Si的后缀求lcp，根据后缀数组的性质，只要从左右两边扫描一遍即可(具体见代码)，最后排除掉S1串中本身重复的子串， 还要注意的是此题有n=0的时候， WA到吐。

#include <iostream>#include <cstdio>#include <cstdlib>#include <cmath>#include <queue>#include <algorithm>#include <vector>#include <cstring>#include <stack>#include <cctype>#include <utility>   #include <map>#include <string>  #include <climits> #include <set>#include <string>    #include <sstream>#include <utility>   #include <ctime>#include <bitset>using std::priority_queue;using std::vector;using std::swap;using std::stack;using std::sort;using std::max;using std::min;using std::pair;using std::map;using std::string;using std::cin;using std::cout;using std::set;using std::queue;using std::string;using std::stringstream;using std::make_pair;using std::getline;using std::greater;using std::endl;using std::multimap;using std::deque;using std::unique;using std::lower_bound;using std::random_shuffle;using std::bitset;typedef long long LL;typedef unsigned long long ULL;typedef pair<int, int> PAIR;typedef multimap<int, int> MMAP;typedef LL TY;const int MAXN(300010);const int MAXM(50010);const int MAXE(100010);const int MAXK(6);const int HSIZE(131313);const int SIGMA_SIZE(52);const int MAXH(19);const int INFI((INT_MAX-1) >> 1);const ULL BASE(31);const LL LIM(10000000);const int INV(-10000);const int MOD(1000000007);const double EPS(1e-7);template<typename T> void checkmax(T &a, T b){if(b > a) a = b;}template<typename T> void checkmin(T &a, T b){if(b < a) a = b;}template<typename T> T ABS(const T &a){return a < 0? -a: a;}char str[100010];struct SA{int S[MAXN];int sa[MAXN], t1[MAXN], t2[MAXN], cnt[MAXN], len, M;void init(int tl, int tm = 128){len = tl;M = tm;int *p1 = t1;int *p2 = t2;for(int i = 0; i < M; ++i) cnt[i] = 0;for(int i = 0; i <= len; ++i) ++cnt[p1[i] = S[i]];for(int i = 1; i < M; ++i) cnt[i] += cnt[i-1];for(int i = len; i >= 0; --i) sa[--cnt[p1[i]]] = i;int temp = 1;for(int k = 1; temp <= len; k <<= 1){temp = 0;for(int i = len-k+1; i <= len; ++i) p2[temp++] = i;for(int i = 0; i <= len; ++i)if(sa[i] >= k)p2[temp++] = sa[i]-k;for(int i = 0; i < M; ++i) cnt[i] = 0;for(int i = 0; i <= len; ++i) ++cnt[p1[p2[i]]];for(int i = 1; i < M; ++i) cnt[i] += cnt[i-1];for(int i = len; i >= 0; --i) sa[--cnt[p1[p2[i]]]] = p2[i];swap(p1, p2);temp = 1;p1[sa[0]] = 0;for(int i = 1; i <= len; ++i)p1[sa[i]] = p2[sa[i-1]] == p2[sa[i]] && p2[sa[i-1]+k] == p2[sa[i]+k]? temp-1: temp++;M = temp;}}int rank[MAXN], height[MAXN];void getHeight(){int k = 0;for(int i = 0; i <= len; ++i)rank[sa[i]] = i;for(int i = 0; i < len; ++i){if(k) --k;int j = sa[rank[i]-1];while(S[i+k] == S[j+k]) ++k;height[rank[i]] = k;}}/*int Log[MAXN];int table[MAXH][MAXN];void initLog(){Log[0] = -1;for(int i = 1; i < MAXN; ++i)Log[i] = (i&(i-1))?Log[i-1]: Log[i-1]+1;}void initRMQ(){for(int i = 1; i <= len; ++i)table[0][i] = height[i];for(int i = 1; (1 << i) <= len; ++i)for(int j = 1; j+(1 << i)-1 <= len; ++j)table[i][j] = min(table[i-1][j], table[i-1][j+(1 << (i-1))]);}int lcp(int a, int b){a = rank[a];b = rank[b];if(a > b) swap(a, b);++a;int temp = Log[b-a+1];return min(table[temp][a], table[temp][b-(1 << temp)+1]);}*/}sa;int len1, len2;int rec[MAXN];int main(){int TC, n_case(0);scanf("%d", &TC);while(TC--){int n;scanf("%d", &n);scanf("%s", str);len2 = len1 = strlen(str);for(int i = 0; i <= len1; ++i)sa.S[i] = str[i];int temp = 'z'+1;for(int i = 0; i < n; ++i){scanf("%s", str);sa.S[len2++] = temp++;int tlen = strlen(str);for(int j = 0; j <= tlen; ++j)sa.S[len2+j] = str[j];len2 += tlen;}sa.init(len2, temp);sa.getHeight();printf("Case %d: ", ++n_case);LL ans;ans = (LL)len1*(len1+1)/2;if(n == 0){for(int i = 1; i <= len1; ++i)ans -= sa.height[i];printf("%I64d\n", ans);continue;}temp = INFI;for(int i = 1; i <= len2; ++i)if(sa.sa[i] <= len1){checkmin(temp, sa.height[i]);rec[i] = temp;}elsetemp = INFI;temp = INFI;for(int i = len2; i >= 1; --i)if(sa.sa[i-1] <= len1){checkmin(temp, sa.height[i]);checkmax(rec[i-1], temp);}elsetemp = INFI;for(int i = 0; i < len1; ++i)if(sa.sa[sa.rank[i]-1] <= len1)checkmax(rec[sa.rank[i]], sa.height[sa.rank[i]]);for(int i = 0; i < len1; ++i)ans -= rec[sa.rank[i]];printf("%I64d\n", ans);}return 0;}