441. Arranging Coins - easy
문제
You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins.
Given n, find the total number of full staircase rows that can be formed.
n is a non-negative integer and fits within the range of a 32-bit signed integer.
제한사항
입출력 예
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Example 1:
n = 5
The coins can form the following rows:
¤
¤ ¤
¤ ¤
Because the 3rd row is incomplete, we return 2.
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Example 2:
n = 8
The coins can form the following rows:
¤
¤ ¤
¤ ¤ ¤
¤ ¤
Because the 4th row is incomplete, we return 3.
풀이
- Math
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func arrangeCoins(n int) int {
res, item := 1, 0
sum := 0
for true {
sum = res + item
if sum < n {
item = sum
res++;
} else if sum == n {
return res
} else {
return res - 1
}
}
return 0
}