manacher算法模板

char a[maxn]; int p[maxn]; //manacher

void manacher(char *s){
    int len = strlen(s+1);
    int m = 2*len+1;
    for(int i=1; i<=len; i++){
        a[i<<1] = s[i];
        a[i<<1|1] = ‘#‘;
    }
    a[0] = ‘+‘; a[1] = ‘#‘; a[m+1] = ‘-‘;
   // cout<<a<<endl;
    int mx=0, idx;for(int i=1; i<=m; i++) {
        if(mx > i)
            p[i] = min(p[2*idx-i], mx-i);
        else
            p[i] = 1;
        for(; a[i-p[i]]==a[i+p[i]]; p[i]++);
        if(p[i]+i > mx) mx = p[i]+i, idx=i;
    }//    for(int i=1; i<=m; i++)
//        cout<<p[i]<<‘ ‘;
//    cout<<endl;
}