/// <summary>
/// 最長共通接頭辞の長さ
/// S[l1:]とother.S[l2:]
/// </summary>
public int GetLcp(RollingHash other, int l1, int l2)
{
if (other == null)
{
throw new ArgumentNullException(nameof(other));
}
int len = Math.Min(S.Length - l1, other.S.Length - l2);
int low = -1, high = len + 1;
while (high - low > 1)
{
var mid = low + (high - low) / 2;
if (!Match(other, l1, l2, mid))
{
high = mid;
}
else
{
low = mid;
}
}
return(low);
}
/// <summary>
/// S[l1:]がotherで始まっているか
/// </summary>
public bool BeginWith(RollingHash other, int l1)
{
if (other == null)
{
throw new ArgumentNullException(nameof(other));
}
return(Match(other, l1, 0, other.S.Length));
}
/// <summary>
/// 全てのModsでS[l,r)が一致するか
/// </summary>
public bool Match(RollingHash other, int l1, int l2, int len)
{
if (other == null)
{
throw new ArgumentNullException(nameof(other));
}
// 範囲外
if (S.Length < l1 + len || other.S.Length < l2 + len)
{
return(false);
}
for (int i = 0; i < _mods.Length; i++)
{
if (GetHash(l1, l1 + len, i) != other.GetHash(l2, l2 + len, i))
{
return(false);
}
}
return(true);
}