题目：

题解：

type Solution struct {m, n, total intmp          map[int]int
}func Constructor(m, n int) Solution {return Solution{m, n, m * n, map[int]int{}}
}func (s *Solution) Flip() (ans []int) {x := rand.Intn(s.total)s.total--if y, ok := s.mp[x]; ok { // 查找位置 x 对应的映射ans = []int{y / s.n, y % s.n}} else {ans = []int{x / s.n, x % s.n}}if y, ok := s.mp[s.total]; ok { // 将位置 x 对应的映射设置为位置 total 对应的映射s.mp[x] = y} else {s.mp[x] = s.total}return
}func (s *Solution) Reset() {s.total = s.m * s.ns.mp = map[int]int{}
}