Day 21 - Leftmost column with at least a one

Solution.kt

// https://leetcode.com/explore/challenge/card/30-day-leetcoding-challenge/530/week-3/3306/

class Solution {
    fun leftMostColumnWithOne(binaryMatrix:BinaryMatrix):Int {
        var result = 100
        for (row in 0 until binaryMatrix.dimensions()[0]) {
            result = minOf(result, bs(binaryMatrix, row))
        }
        return if (result == 100) -1 else result
    }
    
    fun bs(matrix: BinaryMatrix, row: Int): Int {
        var a = 0
        var b = matrix.dimensions()[1] - 1
        
        while (a < b) {
            val m = ((a + b) / 2).toInt()
            val currVal = matrix.get(row, m)

            if (currVal == 0) {
                 a = m + 1
            } else {
                b = m - 1
            }
        }
        
        val minimum = minOf(a, b)
        
        if (minimum >= 0 && matrix.get(row, minimum) == 1) {
            return minimum
        } else if (minimum + 1 < matrix.dimensions()[1] 
                    && matrix.get(row, minimum + 1) == 1) {
            return minimum + 1
        } else {
            return 100
        }
    }
}