LeetCode //C - 330. Patching Array

330. Patching Array

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:

Example 2:

Example 3:

Constraints:

• 1 <= nums.length <= 1000
• 1 < = n u m s [ i ] < = 1 0 4 1 <= nums[i] <= 10^4 1<=nums[i]<=104
• nums is sorted in ascending order.
• 1 < = n < = 2 31 − 1 1 <= n <= 2^{31} - 1 1<=n<=231−1

From: LeetCode
Link: 330. Patching Array

---

Solution:

Ideas:

• miss: This variable represents the smallest sum that cannot be achieved with the current elements of the array.
• i: This is the index to traverse the array nums.
• patches: This is the counter for the number of patches needed.

Code:

int minPatches(int* nums, int numsSize, int n) {
    long long miss = 1;  // The smallest sum that we cannot achieve yet
    int i = 0, patches = 0;
    
    while (miss <= n) {
        if (i < numsSize && nums[i] <= miss) {
            miss += nums[i];
            i++;
        } else {
            miss += miss;
            patches++;
        }
    }
    
    return patches;
}