Manacher hdoj 3068 Longest palindrome

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About solving the longest palindrome substring, there are DP practices, but also have the same n^2 but only with O (1) of space, there are kmp, suffix array??

1 intMainvoid)    {2      while(SCANF ("%s", str +1) ==1)  {3         intlen = strlen (str +1);4Memset (DP,false,sizeof(DP));5          for(intI=1; i<=len; ++i) Dp[i][i] =true;6          for(intI=1; i<len; ++i) {7dp[i][i+1] = (Str[i] = = str[i+1]);8         }9         intAns =1;Ten          for(intI=3; i<=len; ++i) { One              for(intj=1; j+i-1<=len; ++j) { A                 if(dp[j+1][j+i-2] && str[j] = = str[j+i-1]) { -dp[j][j+i-1] =true; -Ans =Max (ans, i); the                 } -             } -         } -printf ("%d\n", ans); +     } -  +     return 0; A}

n^2

But the complexity of the n^2 is not over 3068 of the problem, the following with O (n) algorithm to solve

1 /*2 Test Instructions: Finding the longest palindrome (not the longest palindrome sequence)3 Manasher: A good understanding, easy to implement, O (n) time complex very dick algorithm. 4 simply say the principle: first insert the original string between each adjacent to a character that is unlikely to appear in the string, this can solve the parity problem5 then P[i] indicates that I is the center of the palindrome, the longest palindrome length (unilateral), however in the original string ans = max P[i]-16 I think the essence of the algorithm is to seek p[i] full use of the nature of palindrome, skipping some useless scanning7 English version of Chinese version8 */9 /************************************************Ten * Author:running_time One * Created time:2015-8-7 19:27:46 A * File Name:Manacher.cpp -  ************************************************/ -  the#include <cstdio> -#include <algorithm> -#include <iostream> -#include <sstream> +#include <cstring> -#include <cmath> +#include <string> A#include <vector> at#include <queue> -#include <deque> -#include <stack> -#include <list> -#include <map> -#include <Set> in#include <bitset> -#include <cstdlib> to#include <ctime> + using namespacestd; -  the #defineLson L, Mid, RT << 1 * #defineRson mid + 1, R, RT << 1 | 1 $typedefLong Longll;Panax Notoginseng Const intMAXN = 1e5 +10000; - Const intINF =0x3f3f3f3f; the Const intMOD = 1e9 +7; + CharS[MAXN], str[maxn*2]; A intp[maxn*2]; the  + intManacher (void)  { -str[0] ='$'; str[1] ='#'; $     intLen =strlen (s); $      for(intI=0; i<len; ++i) { -str[i*2+2] = S[i]; str[i*2+3] ='#'; -     } theLen = Len *2+2; Str[len] =' /'; -     intMX =0, id =0;Wuyi      for(intI=1; i<len; ++i) { the         if(mx > i) p[i] = min (p[2*id-i], MX-i); -         ElseP[i] =1; Wu          while(Str[i-p[i] [= Str[i+p[i]]) p[i]++; -         if(MX < p[i] +i) { AboutMX = p[i] + i; ID =i; $         } -     } -     intRET =0; -      for(intI=0; i<len; ++i) { ARET =Max (ret, p[i]); +     } the     returnRET-1; - } $  the intMainvoid)    {//hdoj 3068 Longest palindrome the      while(SCANF ("%s", s) = =1)  { theprintf ("%d\n", Manacher ()); the     } -  in     return 0; the}

Manacher hdoj 3068 Longest palindrome