leetcode_1118

Given a year Y and a month M, return how many days there are in that month.

Example 1:

Input: Y = 1992, M = 7 Output: 31 Example 2:

Input: Y = 2000, M = 2 Output: 29 Example 3:

Input: Y = 1900, M = 2 Output: 28

Note:

1583 <= Y <= 2100 1 <= M <= 12

Solutions

1. math

2. Y is a leap year only if (Y % 4 == 0 && Y % 100 %= 0) || (Y % 400 == 0)

class Solution {
public:
    int days[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    int numberOfDays(int Y, int M) {
        int day = days[M - 1];
        if (M == 2 && (Y % 4 == 0 && Y % 100 != 0) || Y % 400 == 0)
            day++;
        return day;
    }
};