209. Minimum Size Subarray Sum
Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn't one, return 0 instead.
Example:
Input: s = 7, nums = [2,3,1,2,4,3]
Output: 2
Explanation: the subarray [4,3] has the minimal length under the problem constraint.
Follow up:
- If you have figured out the O(n) solution, try coding another solution of which the time complexity is O(n log n).
class Solution {
public int minSubArrayLen(int s, int[] nums) {
int start = 0, end = 0;
int min = Integer.MAX_VALUE, sum = 0;
while(end<=nums.length){
if(sum >= s){
min = Math.min(min, end - start);
sum -= nums[start++];
}else{
if(end==nums.length){
end++;
}else{
sum += nums[end++];
}
}
}
return (min == Integer.MAX_VALUE) ? 0:min;
}
}class Solution {
public int minSubArrayLen(int s, int[] nums) {
int start = 0, end = 0;
int min = Integer.MAX_VALUE, sum = 0;
while(end<nums.length){
sum += nums[end++];
while(sum >= s){
min = Math.min(min, end-start);
sum -= nums[start++];
}
}
return (min == Integer.MAX_VALUE) ? 0:min;
}
}