[LeetCode] 441. Arranging Coins

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.

Example 1:

n = 5

The coins can form the following rows:
¤
¤ ¤
¤ ¤

Because the 3rd row is incomplete, we return 2.

Example 2:

n = 8

The coins can form the following rows:
¤
¤ ¤
¤ ¤ ¤
¤ ¤

Because the 4th row is incomplete, we return 3.

排列硬币。你总共有 n 枚硬币，你需要将它们摆成一个阶梯形状，第 k 行就必须正好有 k 枚硬币。给定一个数字 n，找出可形成完整阶梯行的总行数。n 是一个非负整数，并且在32位有符号整型的范围内。

我给出一个网友的思路。

时间O(1)

空间O(1)

Java实现

1 class Solution {
2     public int arrangeCoins(int n) {
3         return (int) (Math.sqrt((double) 2 * n + 0.25) - 0.5);
4     }
5 }

JavaScript实现

1 /**
2  * @param {number} n
3  * @return {number}
4  */
5 var arrangeCoins = function (n) {
6     return Math.floor(Math.sqrt(2 * n + 1 / 4) - 1 / 2);
7 };

LeetCode 题目总结

[LeetCode] 441. Arranging Coins

原文：https://www.cnblogs.com/cnoodle/p/13222616.html