You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: a.go
    path of file: ./repos/codeforces-go/leetcode/season/2021fall/a
    
    the code of the file until where you have to start completion: package main

/*
用哈希表统计差异

*/

// github.com/EndlessCheng/codef
    
func minimumSwitchingTimes(source, target [][]int) (ans int) {
	cnt := map[int]int{}
	for i, row := range source {
		for j, v := range row {
			cnt[v]++
			cnt[target[i][j]]--
		}
	}
	for _, c := range cnt {
		ans += abs(c)
	}
	return ans / 2
}