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EditDistance refactor (#2853)

This commit is contained in:
Grzegorz Piwowarek 2017-10-25 20:18:33 +02:00 committed by GitHub
parent a636f754b0
commit 1da6e1df42
4 changed files with 23 additions and 27 deletions
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21
algorithms/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceBase.java
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@ -1,22 +1,15 @@
package com.baeldung.algorithms.editdistance;
import java.util.Arrays;
public class EditDistanceBase {
public static int costOfSubstitution(char a, char b) {
if (a == b) {
return 0;
}
return 1;
static int costOfSubstitution(char a, char b) {
return a == b ? 0 : 1;
}
public static int min(int... numbers) {
int min = Integer.MAX_VALUE;
for (int x : numbers) {
if (x < min)
min = x;
}
return min;
static int min(int... numbers) {
return Arrays.stream(numbers)
.min().orElse(Integer.MAX_VALUE);
}
}

7
algorithms/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceDynamicProgramming.java
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@ -2,7 +2,7 @@ package com.baeldung.algorithms.editdistance;
public class EditDistanceDynamicProgramming extends EditDistanceBase {
public static int calculate(String x, String y) {
static int calculate(String x, String y) {
int[][] dp = new int[x.length() + 1][y.length() + 1];
for (int i = 0; i <= x.length(); i++) {
@ -14,12 +14,13 @@ public class EditDistanceDynamicProgramming extends EditDistanceBase {
dp[i][j] = i;
else {
dp[i][j] = min(dp[i - 1][j - 1] + costOfSubstitution(x.charAt(i - 1), y.charAt(j - 1)), dp[i - 1][j] + 1, dp[i][j - 1] + 1);
dp[i][j] = min(dp[i - 1][j - 1]
+ costOfSubstitution(x.charAt(i - 1), y.charAt(j - 1)),
dp[i - 1][j] + 1, dp[i][j - 1] + 1);
}
}
}
return dp[x.length()][y.length()];
}
}

9
algorithms/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceRecursive.java
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@ -2,13 +2,15 @@ package com.baeldung.algorithms.editdistance;
public class EditDistanceRecursive extends EditDistanceBase {
public static int calculate(String x, String y) {
static int calculate(String x, String y) {
if (x.isEmpty())
if (x.isEmpty()) {
return y.length();
}
if (y.isEmpty())
if (y.isEmpty()) {
return x.length();
}
int substitution = calculate(x.substring(1), y.substring(1)) + costOfSubstitution(x.charAt(0), y.charAt(0));
int insertion = calculate(x, y.substring(1)) + 1;
@ -16,5 +18,4 @@ public class EditDistanceRecursive extends EditDistanceBase {
return min(substitution, insertion, deletion);
}
}

13
algorithms/src/test/java/com/baeldung/algorithms/editdistance/EditDistanceTest.java
View File

@ -1,16 +1,17 @@
package com.baeldung.algorithms.editdistance;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import static org.junit.Assert.assertEquals;
@RunWith(Parameterized.class)
public class EditDistanceTest extends EditDistanceDataProvider {
String x;
String y;
int result;
private String x;
private String y;
private int result;
public EditDistanceTest(String a, String b, int res) {
super();
@ -21,11 +22,11 @@ public class EditDistanceTest extends EditDistanceDataProvider {
@Test
public void testEditDistance_RecursiveImplementation() {
Assert.assertEquals(result, EditDistanceRecursive.calculate(x, y));
assertEquals(result, EditDistanceRecursive.calculate(x, y));
}
@Test
public void testEditDistance_givenDynamicProgrammingImplementation() {
Assert.assertEquals(result, EditDistanceDynamicProgramming.calculate(x, y));
assertEquals(result, EditDistanceDynamicProgramming.calculate(x, y));
}
}