[leetcode]avoid-flood-in-the-city 避免洪水泛滥

. - 力扣（LeetCode）

class Solution {
public:vector<int> avoidFlood(vector<int>& rains) {vector<int> ans(rains.size(), 1);set<int> st;unordered_map<int, int> mp;for (int i = 0; i < rains.size(); ++i) {if (rains[i] == 0) {st.insert(i);} else {ans[i] = -1;if (mp.count(rains[i])) {auto it = st.lower_bound(mp[rains[i]]);if (it == st.end()) {return {};}ans[*it] = rains[i];st.erase(it);}mp[rains[i]] = i;}}return ans;}
};