鏈接：https://leetcode-cn.com/problems/unique-paths
組合搞定趟卸。C(m+n-2, m-1)
package leetcode
func UniquePaths(m int, n int) int {
t := m
if m > n {
t = n
}
numerator := 1 //分子
for i := 1; i <= t-1; i++ {
numerator *= m + n - 2 - i + 1
}
denominator := 1 //分母
for i := 1; i <= t-1; i++ {
denominator *= i
}
return numerator / denominator
}
