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Minimum Subarray Sum
Given an array of positive integers nums and a positive integer target, return the minimal length of a subarray whose sum is greater than or equal to target. If there is no such subarray, return 0 instead.
Input:
nums = [2, 3, 1, 2, 4, 3]target = 7
Output:
Result = 2
Explanation:
We are looking for the smallest contiguous subarray with a sum greater than or equal to 7. The possible subarrays that meet this condition are:
[2, 3, 1, 2]with a sum of 8 (length 4)[3, 1, 2, 4]with a sum of 10 (length 4)[2, 4, 3]with a sum of 9 (length 3)[4, 3]with a sum of 7 (length 2)
Among these, [4, 3] is the smallest subarray with a sum equal to or greater than 7. Its length is 2, which is the minimal length we are looking for.
If no such subarray exists:
If nums = [1, 1, 1, 1] and target = 5, there is no subarray with a sum of at least 5. Therefore, the output would be 0.
public int minSubArrayLen(int targetSum, int[] numbers) {
int start = 0, end = 0, currentWindowSum = 0;
int minLength = Integer.MAX_VALUE;
for (end = 0; end < numbers.length; end++) {
currentWindowSum += numbers[end];
while (currentWindowSum >= targetSum) {
minLength = Math.min(minLength, end - start + 1);
currentWindowSum -= numbers[start++];
}
}
return minLength == Integer.MAX_VALUE ? 0 : minLength;
}
