Medium
You are given a 0-indexed integer array arr, and an m x n integer matrix mat. arr and mat both contain all the integers in the range [1, m * n].
Go through each index i in arr starting from index 0 and paint the cell in mat containing the integer arr[i].
Return the smallest index i at which either a row or a column will be completely painted in mat.
Example 1:

Input: arr = [1,3,4,2], mat = [[1,4],[2,3]]
Output: 2
Explanation: The moves are shown in order, and both the first row and second column of the matrix become fully painted at arr[2].
Example 2:

Input: arr = [2,8,7,4,1,3,5,6,9], mat = [[3,2,5],[1,4,6],[8,7,9]]
Output: 3
Explanation: The second column becomes fully painted at arr[3].
Constraints:
m == mat.lengthn = mat[i].lengtharr.length == m * n1 <= m, n <= 1051 <= m * n <= 1051 <= arr[i], mat[r][c] <= m * narr are unique.mat are unique.class Solution {
fun firstCompleteIndex(arr: IntArray, mat: Array<IntArray>): Int {
val map: HashMap<Int, Int> = HashMap()
var ans = mat.size * mat[0].size
for (i in arr.indices) {
map.put(arr[i], i)
}
for (i in mat.indices) {
var maxV = 0
for (j in mat[0].indices) {
maxV = maxV.coerceAtLeast(map[mat[i][j]]!!)
}
ans = ans.coerceAtMost(maxV)
}
for (i in mat[0].indices) {
var maxV = 0
for (j in mat.indices) {
maxV = maxV.coerceAtLeast(map[mat[j][i]]!!)
}
ans = ans.coerceAtMost(maxV)
}
return ans
}
}