Online Election
阿新 • • 發佈:2018-12-25
In an election, the i
-th vote was cast for persons[i]
at time times[i]
.
Now, we would like to implement the following query function: TopVotedCandidate.q(int t)
will return the number of the person that was leading the election at time t
.
Votes cast at time t
Example 1:
Input: ["TopVotedCandidate","q","q","q","q","q","q"], [[[0,1,1,0,0,1,0],[0,5,10,15,20,25,30]],[3],[12],[25],[15],[24],[8]] Output: [null,0,1,1,0,0,1] Explanation: At time 3, the votes are [0], and 0 is leading. At time 12, the votes are [0,1,1], and 1 is leading. At time 25, the votes are [0,1,1,0,0,1], and 1 is leading (as ties go to the most recent vote.) This continues for 3 more queries at time 15, 24, and 8.
Note:
1 <= persons.length = times.length <= 5000
0 <= persons[i] <= persons.length
times
is a strictly increasing array with all elements in[0, 10^9]
.TopVotedCandidate.q
is called at most10000
times per test case.TopVotedCandidate.q(int t)
is always called witht >= times[0]
題目理解:
給定一系列時間節點和投票資訊,問給定時刻誰的票數最多
解題思路:
按事件順序,找到每一個時間節點處票數最多的人,用TreeMap儲存時間和候選人代號,查詢的時候查詢最接近但是小於當前時刻的時間節點,返回候選人資訊
程式碼 如下:
class TopVotedCandidate {
TreeMap<Integer, Integer> map = new TreeMap<Integer, Integer>();
public TopVotedCandidate(int[] persons, int[] times) {
int max = 0, len = persons.length;
int[] count = new int[len + 1];
for(int i = 0; i < len; i++) {
int person = persons[i], time = times[i];
count[person]++;
if(count[max] <= count[person])
max = person;
map.put(time, max);
}
}
public int q(int t) {
return map.floorEntry(t).getValue();
}
}
/**
* Your TopVotedCandidate object will be instantiated and called as such:
* TopVotedCandidate obj = new TopVotedCandidate(persons, times);
* int param_1 = obj.q(t);
*/