hiho第一周

#include 
using namespace std;
#define maxn 1000005 //字符串最大长度
char str[maxn], s[2 * maxn];
int p[2 * maxn], l;     // l为字符串实际长度
int Manacher(){
    int pos, maxpos = 0, ret = 1;
    s[0] = '~';
    s[1] = '#';
    for ( int i = 0; i < l; i++){
        s[2 * i + 2] = str[i];
        s[2 * i + 3] = '#';
    }
    s[2 * l + 2] = 0;
    l = l * 2 + 2;
    for ( int i = 0; i < l; i++){
        if ( maxpos > i){
            p[i] = min( p[2 * pos - i], maxpos - i);
        }
        else{
            p[i] = 1;
        }
        while ( s[i + p[i]] == s[i - p[i]]){
            p[i]++;
        }
        if ( p[i] + i > maxpos){
            maxpos = p[i] + i;
            pos = i;
        }
        ret = max( ret, p[i]);
    }
    return ret - 1;
}
int main()
{
    int t;

    scanf( "%d", &t);
    while ( t--){
        scanf( "%s", str);
        l = strlen( str);
        printf( "%d\n", Manacher());
    }
    return 0;
}