https://leetcode.com/problems/snapshot-array

snapshot-array.go

type SnapshotArray struct {
    hash    map[int]map[int]int
    snap    int
}


func Constructor(length int) SnapshotArray {
    array := SnapshotArray{
        map[int]map[int]int{},
        0,
    }
    for i:=0;i<length;i++ {
        array.hash[i] = map[int]int{}
    }
    return array
}


func (this *SnapshotArray) Set(index int, val int)  {
    this.hash[index][this.snap] = val
}


func (this *SnapshotArray) Snap() (snap int) {
    // fmt.Println("snap, current:", this.snap)
    snap = this.snap
    this.snap++
    return
}


func (this *SnapshotArray) Get(index int, snap_id int) (ret int) {
    id := snap_id
    for id >= 0{
        _, ok := this.hash[index][id]
        if ok {
            break
        }
        id--
    }
    if id < 0 {
        return 0
    }
    ret = this.hash[index][id]
    // fmt.Println("Getting index:", index, "from snap_id:", snap_id, "ret:", ret )
    return
}


/**
 * Your SnapshotArray object will be instantiated and called as such:
 * obj := Constructor(length);
 * obj.Set(index,val);
 * param_2 := obj.Snap();
 * param_3 := obj.Get(index,snap_id);
 */