UVa 11888 Abnormal 89's
方法：Manacher
Manacher算法在O(length) 时间内求出各个回文子串的长度。O(length) 时间检查时那一种情况。
code:
1 #include <cstdio> 2 #include <cstring> 3 #include <algorithm> 4 #include <iostream> 5 #include <string> 6 #include <vector> 7 #include <stack> 8 #include <bitset> 9 #include <cstdlib> 10 #include <cmath> 11 #include <set> 12 #include <list> 13 #include <deque> 14 #include <map> 15 #include <queue> 16 #include <fstream> 17 #include <cassert> 18 #include <unordered_map> 19 #include <unordered_set> 20 #include <cmath> 21 #include <sstream> 22 #include <time.h> 23 #include <complex> 24 #include <iomanip> 25 #define Max(a,b) ((a)>(b)?(a):(b)) 26 #define Min(a,b) ((a)<(b)?(a):(b)) 27 #define FOR(a,b,c) for (ll (a)=(b);(a)<(c);++(a)) 28 #define FORN(a,b,c) for (ll (a)=(b);(a)<=(c);++(a)) 29 #define DFOR(a,b,c) for (ll (a)=(b);(a)>=(c);--(a)) 30 #define FORSQ(a,b,c) for (ll (a)=(b);(a)*(a)<=(c);++(a)) 31 #define FORC(a,b,c) for (char (a)=(b);(a)<=(c);++(a)) 32 #define FOREACH(a,b) for (auto &(a) : (b)) 33 #define rep(i,n) FOR(i,0,n) 34 #define repn(i,n) FORN(i,1,n) 35 #define drep(i,n) DFOR(i,n-1,0) 36 #define drepn(i,n) DFOR(i,n,1) 37 #define MAX(a,b) a = Max(a,b) 38 #define MIN(a,b) a = Min(a,b) 39 #define SQR(x) ((LL)(x) * (x)) 40 #define Reset(a,b) memset(a,b,sizeof(a)) 41 #define fi first 42 #define se second 43 #define mp make_pair 44 #define pb push_back 45 #define all(v) v.begin(),v.end() 46 #define ALLA(arr,sz) arr,arr+sz 47 #define SIZE(v) (int)v.size() 48 #define SORT(v) sort(all(v)) 49 #define REVERSE(v) reverse(ALL(v)) 50 #define SORTA(arr,sz) sort(ALLA(arr,sz)) 51 #define REVERSEA(arr,sz) reverse(ALLA(arr,sz)) 52 #define PERMUTE next_permutation 53 #define TC(t) while(t--) 54 #define forever for(;;) 55 #define PINF 1000000000000 56 #define newline '\n' 57 58 #define test if(1)if(0)cerr 59 using namespace std; 60 using namespace std; 61 typedef vector<int> vi; 62 typedef vector<vi> vvi; 63 typedef pair<int,int> ii; 64 typedef pair<double,double> dd; 65 typedef pair<char,char> cc; 66 typedef vector<ii> vii; 67 typedef long long ll; 68 typedef unsigned long long ull; 69 typedef pair<ll, ll> l4; 70 const double pi = acos(-1.0); 71 72 73 const int maxn = 2e5+1; 74 char ma[maxn*2]; 75 int p[maxn*2]; 76 int l; 77 void Manacher(const string &str) 78 { 79 int len = str.length(); 80 l = 0; 81 ma[l++] = '$'; 82 ma[l++] = '#'; 83 rep(i, len) 84 { 85 ma[l++] = str[i]; 86 ma[l++] = '#'; 87 } 88 ma[l] = 0; 89 int pnow = 0, pid = 0; 90 for (int i = 1; i < l; ++i) 91 { 92 if (pnow > i) p[i] = min(p[2*pid-i], pnow-i); 93 else p[i] = 1; 94 for (; ma[i-p[i]] == ma[i+p[i]]; ++p[i]); 95 if (i+p[i] > pnow) 96 { 97 pnow = i+p[i]; pid = i; 98 } 99 } 100 } 101 /* 102 abaaba 103 . , a , b , a , a , b , a , 104 0 1 2 1 4 1 2 7 2 1 4 1 2 1 105 0 1 2 3 4 5 6 7 8 9 10 11 12 13 106 */ 107 int main() 108 { 109 int T; cin >> T; 110 repn(kase, T) 111 { 112 string str; 113 cin >> str; 114 Manacher(str); 115 116 bool done = false; 117 for (int i = 2; i < (1+l)/2; ++i) 118 if (p[i] == i && p[(i+p[i]-1+l)/2] == l-(i+p[i]-1+l)/2) 119 { 120 cout << "alindrome\n"; 121 done = true; 122 break; 123 } 124 if (!done) 125 if (p[(l+1)/2]-1 == str.length()) 126 cout << "palindrome\n"; 127 else 128 cout << "simple\n"; 129 130 } 131 }
