Package g1401_1500.s1488_avoid_flood_in_the_city

Class Solution

java.lang.Object
g1401_1500.s1488_avoid_flood_in_the_city.Solution
public class Solution extends Object
1488 - Avoid Flood in The City\. Medium Your country has an infinite number of lakes. Initially, all the lakes are empty, but when it rains over the `nth` lake, the `nth` lake becomes full of water. If it rains over a lake which is **full of water** , there will be a **flood**. Your goal is to avoid the flood in any lake. Given an integer array `rains` where: * `rains[i] > 0` means there will be rains over the `rains[i]` lake. * `rains[i] == 0` means there are no rains this day and you can choose **one lake** this day and **dry it**. Return _an array `ans`_ where: * `ans.length == rains.length` * `ans[i] == -1` if `rains[i] > 0`. * `ans[i]` is the lake you choose to dry in the `ith` day if `rains[i] == 0`. If there are multiple valid answers return **any** of them. If it is impossible to avoid flood return **an empty array**. Notice that if you chose to dry a full lake, it becomes empty, but if you chose to dry an empty lake, nothing changes. (see example 4) **Example 1:** **Input:** rains = [1,2,3,4] **Output:** [-1,-1,-1,-1] **Explanation:** After the first day full lakes are [1] After the second day full lakes are [1,2] After the third day full lakes are [1,2,3] After the fourth day full lakes are [1,2,3,4] There's no day to dry any lake and there is no flood in any lake. **Example 2:** **Input:** rains = [1,2,0,0,2,1] **Output:** [-1,-1,2,1,-1,-1] **Explanation:** After the first day full lakes are [1] After the second day full lakes are [1,2] After the third day, we dry lake 2. Full lakes are [1] After the fourth day, we dry lake 1. There is no full lakes. After the fifth day, full lakes are [2]. After the sixth day, full lakes are [1,2]. It is easy that this scenario is flood-free. [-1,-1,1,2,-1,-1] is another acceptable scenario. **Example 3:** **Input:** rains = [1,2,0,1,2] **Output:** [] **Explanation:** After the second day, full lakes are [1,2]. We have to dry one lake in the third day. After that, it will rain over lakes [1,2]. It's easy to prove that no matter which lake you choose to dry in the 3rd day, the other one will flood. **Constraints:** * 1 <= rains.length <= 105 * 0 <= rains[i] <= 109

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • avoidFlood

      public int[] avoidFlood(int[] rains)