Problema
One move increases one array value by 1. Make the array nondecreasing: each value must be greater than or equal to the one immediately before it. You may not decrease values or reorder them.
Implement increasing_array(numbers).
Input
numbers: The values in their original order.
Output
Return the minimum total number of unit increments.
Vincoli
1 ≤ length ≤ 200,000. Each value is between 1 and 1,000,000,000. Use a signed 64-bit result.
Esempi
Input:
numbers = [4, 1, 3]
Output atteso:
expected = 4Input:
std::vector<long long> numbers = {4, 1, 3};
Output atteso:
long long expected = 4;Input:
long[] numbers = new long[] {4, 1, 3};
Output atteso:
long expected = 4;Spiegazione
Raise 1 to 4 using three moves and 3 to 4 using one move. The result [4, 4, 4] uses four moves.
Input:
numbers = [1, 2, 2, 5]
Output atteso:
expected = 0Input:
std::vector<long long> numbers = {1, 2, 2, 5};
Output atteso:
long long expected = 0;Input:
long[] numbers = new long[] {1, 2, 2, 5};
Output atteso:
long expected = 0;Spiegazione
Every value is already at least the preceding value; equal neighbors are allowed.
Come affrontarlo
Prova prima da solo, poi apri un suggerimento alla volta.
Suggerimento 1
Scan from left to right, because each value only depends on the previous one.
Suggerimento 2
Whenever a value is too small, raise it just enough to match the running minimum allowed value.
Suggerimento 3
Track the total increments carefully, since earlier increases affect later comparisons.
Complessità attesa
O(n) time, O(1) extra space
Riferimenti
Questa sfida è adattata per CodeUtility. Segui la traccia e i vincoli sopra.