###### tags: `LeetCode` `HackRank`

# HackRank Frequency Queries

## Goal

按照輸入的array做事情
Operation ( a , b)

a = 1 , 陣列新增1個b
a = 2 , 陣列刪除1個b
a = 3 , 查看陣列中是否有b個個數的元素,有印出1,沒有印出0

## Solution

func freqQuery(queries [][]int32) []int32 {

    
    m := make(map[int32]int32) //數字b出現的次數     1 1 1 2 2 2 3 3 4 [1]=3,[2]=3,[3]=2,[4]=1
    times := make(map[int32]int32) // 儲存出現的次數    [3]=2,[2]=1,[1]=1
    
    ans := []int32{}
    for i:=0 ; i< len(queries) ; i++ {
        first := queries[i][0]
        second := queries[i][1]
        
        switch(first) {
            case 1:
                m[second]++
                times[m[second]]++
                times[m[second]-1]--
            case 2:
                m[second]--
                times[m[second]+1]--
                times[m[second]]++
            case 3:
                v ,ok := times[second] 
                if ok && v!=0{
                    ans = append(ans,1)
                }else{
                    ans = append(ans,0)
                }
        }
    }
    
    return ans
}