HTMLify

class Solution:
    def minMen(self, arr):
        n = len(arr)
        max_reach_at = [-1] * n
        
        for i in range(n):
            if arr[i] != -1:
                left = max(0, i - arr[i])
                right = min(n - 1, i + arr[i])
                max_reach_at[left] = max(max_reach_at[left], right)
        
        workers = 0
        current_end = -1
        farthest = -1
        
        for i in range(n):
            farthest = max(farthest, max_reach_at[i])
            
            if farthest < i:
                return -1
                
            if i > current_end:
                workers += 1
                current_end = farthest
                
        return workers