#####   ######  #####    ###    #   #  ###  #   #  ######
##  ##  ##      ##  ##  ## ##   #   #   #   #   #  ##
#####   ####    #####   #   #   #   #   #   #   #  ####
##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/greedy-algorithms/advanced-greedy/patching-array-implementation

░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░████████████████████████████████████████████████████████████████████████████████████████████

#####   ######  #####    ###    #   #  ###  #   #  ######
##  ##  ##      ##  ##  ## ##   #   #   #   #   #  ##
#####   ####    #####   #   #   #   #   #   #   #  ####
##  #   ##      ##      ## ##    # #    #    # #   ##
##   #  ######  ##       ###      #    ###    #    ######

$ curl repovive.com/roadmaps/greedy-algorithms/advanced-greedy/patching-array-implementation

Repovive

Patching Array - Implementation - Advanced Greedy | Greedy Algorithms | Repovive

Repovive.

Greedy Algorithms8 sections · 317 units14h total

Open in Course

Patching Array - Implementation

The code

Here is the solution:

function minPatches(nums, n)
 patches := 0
 miss := 1
 i := 0
 while miss <= n
 if i < length(nums) and nums[i] <= miss then
 miss := miss + nums[i]
 i := i + 1
 else
 miss := miss + miss
 patches := patches + 1
 return patches

Time: $O(m + \log n)$ where $m$ is array length. Space: $O(1)$ .

Either use an existing number to extend range, or patch with $miss$ to double the range. Doubling means $O(\log n)$ patches at most.