HDU 3294 Girls' research 字符串-manacher算法

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题目地址：http://acm.hdu.edu.cn/showproblem.php?pid=3294

字符串————

AC代码：

#include <iostream>#include <cstdio>#include <cstring>#include <string>#include <cstdlib>#include <cmath>#include <vector>#include <list>#include <deque>#include <queue>#include <iterator>#include <stack>#include <map>#include <set>#include <algorithm>#include <cctype>using namespace std;typedef __int64 LL;const int N=400109;const LL II=1000000007;const int INF=0x3f3f3f3f;const double PI=acos(-1.0);char xh[N],s[N],pi[26];int p[N],len;void manacher(char *str){int mx=0;//记录前面回文串最长影响到的地方。不一定是最长回文串造成的。int id;//最长影响串的idint ans=0,t;//最长结果for(int i=1;i<len;i++){if(mx>i)    p[i]=min(p[2*id-i],mx-i);elsep[i]=1;while(str[i+p[i]]==str[i-p[i]]){            p[i]++;}if(i+p[i]>mx){mx=i+p[i];id=i;}if(p[i]>ans)ans=p[i],t=i;}ans--;if(ans<2){    printf("No solution!\n");    return ;}int j=t-(ans-1);printf("%d %d\n",j/2-1,j/2+ans-2);for(int i=0;i<ans;i++,j+=2)        printf("%c",pi[str[j]-'a']);    printf("\n");}int main(){    int i,j,l;    char c,a;while(scanf("%c%s",&c,s)!=EOF){    l=c-'a';    for(i=0;i<26;i++)            pi[i]=(i+26-l)%26+'a';    getchar();//这个地方要注意        len=strlen(s);        xh[0]='$';xh[1]='#';        for(i=0,l=2;i<len;i++,l+=2)        {            xh[l]=s[i];            xh[l+1]='#';        }        len=len*2+2;manacher(xh);}return 0;}