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441.Arranging Coins
441.Arranging Coins
难度:Easy
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.
简单的等差数列求项数的题目，一元二次方程求根公式。
class Solution {
public:
int arrangeCoins(int n) {
return int((sqrt(1+8.0*n)-1)/2);
}
};
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Last modified 1yr ago