Substitution Cipher spojSCYPHER

http://www.spoj.com/problems/SCYPHER/

拓扑排序，要求是全序集

#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>#include <iomanip>//#pragma comment(linker, "/STACK:102400000,102400000")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;using std::upper_bound;using std::multiset;using std::ios;using std::make_heap;using std::push_heap;using std::pop_heap;typedef long long LL;typedef unsigned long long ULL;typedef unsigned UN;typedef pair<ULL, ULL> PAIR;typedef multimap<int, int> MMAP;typedef long double LF;const int MAXN(30);const int MAXM(310);const int MAXE(310);const int MAXK(6);const int HSIZE(131313);const int SIGMA_SIZE(26);const int MAXH(18);const int INFI((INT_MAX-1) >> 1);const ULL BASE(31);const LL LIM(1e13);const int INV(-10000);const int MOD(1000000007);const double EPS(1e-7);const LF PI(acos(-1.0));template<typename T> inline void checkmax(T &a, T b){if(b > a) a = b;}template<typename T> inline void checkmin(T &a, T b){if(b < a) a = b;}template<typename T> inline T ABS(const T &a){return a < 0? -a: a;}bool E[MAXN][MAXN];int indeg[MAXN];int mp[MAXN];char str[10010][1010];void dfs(int l, int r, int dep){if(l == r) return;int tl = l, tr;while(tl < r){while(tl <= r && str[tl][dep] == '\0') ++tl;tr = tl+1;while(tr <= r && str[tr][dep] == str[tl][dep]) ++tr;if(tr <= r && str[tr][dep] != '\0') {indeg[str[tr][dep]-'a'] += E[str[tl][dep]-'a'][str[tr][dep]-'a']? 0: 1;E[str[tl][dep]-'a'][str[tr][dep]-'a'] = true;}dfs(tl, tr-1, dep+1);tl = tr;}}int que[MAXN], front, back;bool solve(int n){front = back = 0;for(int i = 0; i < n; ++i)if(indeg[i] == 0){que[back++] = i;indeg[i] = -1;}while(front < back){if(back-front > 1) return false;while(front < back){int cur = que[front];mp[cur] = front++;for(int i = 0; i < n; ++i)if(E[cur][i])--indeg[i];}for(int i = 0; i < n; ++i)if(indeg[i] == 0){que[back++] = i;indeg[i] = -1;}}if(back < n) return false;return true;}int main(){int TC;scanf("%d", &TC);while(TC--){int n, K;scanf("%d%d", &n, &K);memset(E, 0, sizeof(E));memset(indeg, 0, sizeof(indeg));for(int i = 0; i < K; ++i) {scanf("%s", str[i]);int len = strlen(str[i]);}while(getchar() != '\n');dfs(0, K-1, 0);char temp;if(solve(n)){while((temp = getchar()), temp != '\n' && temp != EOF){if(temp >= 'a' && temp-'a' < n) putchar(mp[temp-'a']+'a');else putchar(temp);}putchar('\n');}else{printf("Message cannot be decrypted.\n");while((temp = getchar()), temp != '\n' && temp != EOF);}}return 0;}