package q74

func searchMatrix(matrix [][]int, target int) bool {
	w, h := len(matrix[0]), len(matrix)
	idx := func(i int) (int, int) { return i / w, i % w }

	l, r := 0, w*h
	for l < r {
		m := (l + r) / 2
		row, col := idx(m)
		switch {
		case matrix[row][col] == target:
			return true
		case matrix[row][col] < target:
			l = m + 1
		default:
			r = m
		}
	}
	return false
}

var _ = searchMatrix