LeetCode | 441. Arranging Coins 水题

You have a total of n coinsthat you want to form in a staircase shape, where every k-throw must have exactly k coins.

Given n, findthe total number of full staircaserows that can be formed.

n is a non-negative integer andfits 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.

这是一道水题，我使用的是一般人都会使用的方法，就是从1一直加，直到大于n，就能得到可以填满几层，在使用这个方法的时候要注意，数据的范围可能会超出int，要使用long long ，还需要注意，当n刚好可以填满几层的时候这种情况需要注意一下

class Solution {

public:

   int arrangeCoins(int n) {

      long long collect = 0;

      int u = 1;

      while (collect <= n)

      {

            collect += u;

            u++;

      }

      return u - 2;

}

};