Problem
Given a sorted integer array nums and an integer n, add/patch elements to the array such that any number in the range [1, n] inclusive can be formed by the sum of some elements in the array.
Return the minimum number of patches required.
Example 1:
Input: nums = [1,3], n = 6
Output: 1
Explanation:
Combinations of nums are [1], [3], [1,3], which form possible sums of: 1, 3, 4.
Now if we add/patch 2 to nums, the combinations are: [1], [2], [3], [1,3], [2,3], [1,2,3].
Possible sums are 1, 2, 3, 4, 5, 6, which now covers the range [1, 6].
So we only need 1 patch.
Example 2:
Input: nums = [1,5,10], n = 20
Output: 2
Explanation: The two patches can be [2, 4].
Example 3:
Input: nums = [1,2,2], n = 5
Output: 0
Constraints:
1 <= nums.length <= 10001 <= nums[i] <= 10^4numsis sorted in ascending order.1 <= n <= 2^31 - 1
Solution
/**
* @param {number[]} nums
* @param {number} n
* @return {number}
*/
var minPatches = function(nums, n) {
var miss = 1;
var count = 0;
var i = 0;
while (miss <= n) {
if (i < nums.length && nums[i] <= miss) {
miss += nums[i++];
} else {
miss += miss;
++count;
}
}
return count;
};
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).