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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file StringUtils.h
* @author Balajiganapathi S <balajiganapathi.s@gmail.com>
* @date 2017
*
* String routines
*/
#include "StringUtils.h"
#include <algorithm>
#include <string>
#include <vector>
using namespace std;
using namespace dev;
namespace dev
{
bool stringWithinDistance(string const& _name1, string const& _name2, size_t _maxDistance)
{
if (_name1 == _name2)
return true;
size_t n1 = _name1.size(), n2 = _name2.size();
vector<vector<size_t>> dp(n1 + 1, vector<size_t>(n2 + 1));
// In this dp formulation of Damerau–Levenshtein distance we are assuming that the strings are 1-based to make base case storage easier.
// So index accesser to _name1 and _name2 have to be adjusted accordingly
for (size_t i1 = 0; i1 <= n1; ++i1)
{
for (size_t i2 = 0; i2 <= n2; ++i2)
{
if (min(i1, i2) == 0)
// Base case
dp[i1][i2] = max(i1, i2);
else
{
dp[i1][i2] = min(dp[i1 - 1][i2] + 1, dp[i1][i2 - 1] + 1);
// Deletion and insertion
if (_name1[i1 - 1] == _name2[i2 - 1])
// Same chars, can skip
dp[i1][i2] = min(dp[i1][i2], dp[i1 - 1][i2 - 1]);
else
// Different chars so try substitution
dp[i1][i2] = min(dp[i1][i2], dp[i1 - 1][i2 - 1] + 1);
if (i1 > 1 && i2 > 1 && _name1[i1 - 1] == _name2[i2 - 2] && _name1[i1 - 2] == _name2[i2 - 1])
// Try transposing
dp[i1][i2] = min(dp[i1][i2], dp[i1 - 2][i2 - 2] + 1);
}
}
}
size_t distance = dp[n1][n2];
// if distance is not greater than _maxDistance, and distance is strictly less than length of both names,
// they can be considered similar this is to avoid irrelevant suggestions
return distance <= _maxDistance && distance < n1 && distance < n2;
}
}
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