HDU 3068 Longest Palindrome "Manacher to find the longest palindrome string, template Problem"

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The longest palindrome Time limit:4000/2000 MS (java/others) Memory limit:32768/32768 K (java/others)
Total submission (s): 11760 Accepted Submission (s): 4308
Link: Click me!
Problem description gives a string s that consists only of lowercase English characters a,b,c...y,z, seeking the length of the longest palindrome in S.
Palindrome is the same as the positive and negative reading is the same string, such as ABA, ABBA input has multiple sets of case, not more than 120 groups, each set of input is a line of lowercase English characters a,b,c...y,z a string s
Between two sets of case separated by a blank line (the empty line is not processed)
String length len <= 110000 output An integer x for each row, corresponding to a set of case, representing the longest palindrome length contained in the string for the group case.
Sample Input

Aaaaabab

Sample Output

43

Analysis:

To solve the longest palindrome string, I used to do with DP, in this topic, O (n^2) complexity is sure to be timed out, so I first knocked on a manacher template today, very convenient, complexity also reduced an order of magnitude, the complexity of only O (N), Orz ...

Implementation code:

#include <map> #include <cmath> #include <queue> #include <vector> #include <cstdio># Include <string> #include <cstring> #include <sstream> #include <iostream> #include < algorithm>using namespace std; #define FIN freopen ("Input.txt", "R", stdin) #define FOUT freopen ("ou Tput.txt "," w ", stdout) #define CASE (T) int t;for (scanf ("%d ", &t);  t--;) const int MAXN = 110000 + 5;char ma[maxn << 1];int mp[maxn << 1];void manacher (char s[], int len) {int    L = 0;    ma[l++] = ' $ ';    ma[l++] = ' # ';        for (int i = 0; i < len; i++) {ma[l++] = s[i];    ma[l++] = ' # ';    } Ma[l] = 0;    int mx = 0, id = 0;        for (int i = 0; i < L; i++) {mp[i] = mx > I min (mp[2 * id-i], mx-i): 1;        while (Ma[i + mp[i]] = = Ma[i-mp[i]]) mp[i]++;            if (i + mp[i] > mx) {mx = i + mp[i];        id = i; }}}char S[maxn];int Main () {#ifndef Online_judGE FIN; #endif//Online_judge while (~scanf ("%s", s)) {int len = strlen (s);        Manacher (S, Len);        int ans = 0;        for (int i = 0; i < 2 * len + 2; i++) {ans = max (ans, mp[i]-1);    } printf ("%d\n", ans); } return 0;}

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HDU 3068 Longest Palindrome "Manacher to find the longest palindrome string, template Problem"