2403. Minimum Time to Kill All Monsters
You are given an integer array power where power[i] is the power of the ith monster.
You start with 0 mana points, and each day you increase your mana points by gain where gain initially is equal to 1.
Each day, after gaining gain mana, you can defeat a monster if your mana points are greater than or equal to the power of that monster. When you defeat a monster:
- your mana points will be reset to 0, and
- the value of gain increases by 1.
Return the minimum number of days needed to defeat all the monsters.