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Merge pull request #10556 from sk1418/maxSubArr 

fix the initial maxSum and add test
This commit is contained in:
Eric Martin 2021-03-20 21:39:43 -05:00 committed by GitHub
parent ce2e455d58 0290234485
commit 665184ffda
2 changed files with 16 additions and 5 deletions
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8
algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/maximumsubarray/KadaneAlgorithm.java
View File

@ -13,22 +13,22 @@ public class KadaneAlgorithm {
int start = 0;
int end = 0;
int maxSoFar = 0, maxEndingHere = 0;
int maxSoFar = arr[0], maxEndingHere = arr[0];
for (int i = 0; i < size; i++) {
if (arr[i] > maxEndingHere + arr[i]) {
start = i;
maxEndingHere = arr[i];
} else
} else {
maxEndingHere = maxEndingHere + arr[i];
}
if (maxSoFar < maxEndingHere) {
maxSoFar = maxEndingHere;
end = i;
}
}
logger.info("Found Maximum Subarray between {} and {}", start, end);
logger.info("Found Maximum Subarray between {} and {}", Math.min(start, end), end);
return maxSoFar;
}
}

13
algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/maximumsubarray/KadaneAlgorithmUnitTest.java
View File

@ -9,11 +9,22 @@ class KadaneAlgorithmUnitTest {
@Test
void givenArrayWithNegativeNumberWhenMaximumSubarrayThenReturns6() {
//given
int[] arr = new int[]{-3, 1, -8, 4, -1, 2, 1, -5, 5};
int[] arr = new int[] { -3, 1, -8, 4, -1, 2, 1, -5, 5 };
//when
KadaneAlgorithm algorithm = new KadaneAlgorithm();
int maxSum = algorithm.maxSubArraySum(arr);
//then
assertEquals(6, maxSum);
}
@Test
void givenArrayWithAllNegativeNumbersWhenMaximumSubarrayThenReturnsExpectedResult() {
//given
int[] arr = new int[] { -8, -7, -5, -4, -3, -1, -2 };
//when
KadaneAlgorithm algorithm = new KadaneAlgorithm();
int maxSum = algorithm.maxSubArraySum(arr);
//then
assertEquals(-1, maxSum);
}
}